Excel spreadsheet showing CH2 and natC target thicknesses attached

See attached for the logbook

See attached pictures for measurements of the 7Be(p,p) chamber dimensions.

The target ladder center - Far S2 distance = 50 + 95 + 0.85 - (19.22+19.58)/2 = 126.45 mm

On 29/11/2018 at 17:40 a rough measurement of the irradiated target activity was performed using a geiger counter.

The geiger counter was a calibrated Berthold LB124, which was placed a fixed 15mm distance from each target.

The calibration was such that 1cps = 37kBq.

The LB124 counter measured a background count of 0.5cps

See attached for S2 electronics map, following channels from S2 outputs to ADC inputs

For the 19/11/2018 - 29/11/2018 beamtime only the Far S2 was in operation

To be shipped back to Edinburgh for repair:

On 29/11/2018:

Dismounted S2 2323-18 (496um), 12um mylar, diode, and diodes 0.9um mylar.

Performed general cleanup of lab. Boxed away cables and other parts. See attached pictures 1, 2, 3, and 4.

See attached picture 5, 6, 7, and 8 for status of electronics and target chamber at end of beamtime.
 

Diode Ortec 571 Amplifier Settings:

• Fine gain: 10 (0.5 ->1.5)
• Course gain: 50
• Shaping time: 0.5us
• BLR AUTO: ON
• NEG: ON (Instead of POS)
• OUT: ON (Instead of Delay)
• Internal fine gain: 1X

Diode quad TFA settings:

• No clipping cable attached
• Internal jumpers:
• W1: Invert
• W2 and W3: 200ns differentiation
• W4: T2 (not set to 50ns or OUT)
• W5: X5 course gain

Diode quad CFD settings:

• Threshold at minimum: -177.6mV
• Short delay cable attached (1ns)
• Internal jumpers:
• W1: no jumper
• W2: Top
• W3: no jumper

Oscilloscope used: Tektronix TDS 3054B

RAL Crate Configuration:

On 28/11/2018:

Mounted 12um mylar in front of far S2 - see attached pictures 1 and 2

In air: Far S2 biased to -130.0V, leak I = 1.61uA. Diode biased to -70.1V, leak I = 0.01uA -> 0.00uA. Rate meter ~ 4500Hz.

Detectors switched off

17:50 started Ecodry 1 and 2, started opening manual valve.

18:00 Manual valve fully opened, T1600 backing valve opened, Turbos switched on.

Once pressures ~ 1e-5mBar, far S2 bias = -130.0V, leak I = 1.59uA. Diode bias = -70.1V, leak I = 0.00uA.

18:08 Pressures (mBar):

• TPU1 = 3.0e-5
• TPU2 = 6.0e-5
• TPD1 = 5.2e-6
• TPD2 = 8.7e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Run # 181128181421

• Run time: 1799s
• Pulser ON, as before
• Alpha source
• S2 mylar: 12um
• DT ~ 12%

Started overnight run:

Run # 181128184505

• Run time: 51706s
• Pulser ON, as before
• Alpha source
• S2 mylar: 12um
• DT ~ 8%
• See attached picture 3 for sample far S2 front strip spectrum

18:50 End of day check:

Far S2 bias = -130.0V, leak I = 1.60uA.

Diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 3.8e-6
• TPU2 = 1.2e-6
• TPD1 = 1.4e-6
• TPD2 = 1.6e-6
• CHUP = Sensor Off
• CHDW = No Sensor

On 29/11/2018: Alpha run stopped

9:05: Far S2 bias = -130.0V, leak I = 1.70uA. Diode bias = -70.1V, leak I = 0.00uA.

Detector biases and preamps off.

Pressures (mBar):

• TPU1 = 7.6e-7
• TPU2 = 3.5e-7
• TPD1 = 7.7e-7
• TPD2 = 7.3e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Closed manual and T1600 backing valves. Stopped turbos. Stopped Ecodry 1 and 2.

Switched off Nim bin, RAL crate, and CAMAC crate

9:45 Opened venting valve

On 28/11/2018:

At 13:35: Far S2 bias = -130.0V, leak I = 1.55uA. Diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 3.3e-6
• TPU2 = 9,3e-7
• TPD1 = 1.2e-6
• TPD2 = 1.3e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Switched off detectors, switched off pumps, closed manual and T1600 backing valves. Vented chamber.

Removed 0.9um mylar from far S2 - see attached picture 1 for mylar pre-removal. Removed far iris arm from downstream lid -> set iris to open position. Replaced far iris actuator with blank flange.

Remounted far S2 and far preamp - preamp still draws correct currents.

In air: Far S2 bias = -130.0V, leak I = 1.65uA. Diode bias = -70.1V, leak I = 0.01uA. Rate meter ~ 5500Hz.

Detectors bias off.

15:05 Ecodry 1 and 2 on, started opening manual valve.

15:20 Manual valve fully opened, T1600 backing valve opened, turbos on

15:30 Pressures (mBar):

• TPU1 = 2.2e-5
• TPU2 = 4.4e-6
• TPD1 = 4.0e-6
• TPD2 = 4.7e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Far S2 biased to 130.0V, leak I = 1.59uA. Diode biased to -70.1V, leak I = 0.00uA. Ratemeter ~ 7000Hz.

Run numbers 181128153642, 181128161647, and 181128161758 are all alpha calibration runs. However DAQ connection was lost before the first run was started so the run time is not recorded for these.

Run # 181128162552

• Run time: 1408s
• Pulser ON, as before
• Alpha source
• S2 mylar: NONE
• DT ~ 20%
• See attached picture 2 for sample spectra from ADC2 Ch7 (ADC 3 in FAIR DAQ file browser)

16:45 Far S2 bias = -130.0V, leak I = 1.61uA. diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 2.8e-6
• TPU2 = 8.8e-7
• TPD1 = 1.2e-6
• TPD2 = 1.2e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Switched off detectors, closed valves, turned off pumps, vented chamber.

On 28/11/2018:

After pulser walkthrough (see eLog entry #67)

Dismounted targets from ladder - see picture 1 and 2 for upstream and downstream sides respectively

Mounted alpha source on ladder - see pictures 3 and 4 for upstream and downstream sides respectively

New target ladder configuration is now:

Dismounted thin CH2 target 50 - it was still attached to the collimator.

Remounted far S2 with 0.9um mylar, remounted far iris arm.

In air, pressures (mBar):

• TPU1 > 1000
• TPU2 > 1000
• TPD1 = 170 (above range)
• TPD2 = 73 (above range)
• CHUP = Sensor Off
• CHDW = No Sensor

Far S2 biased to -130.0V, leak I = 1.55uA. Diode biased to -70.1V, leak I = 0.01uA.

Ratemeter ~9200Hz.

Switched off detectors.

12:05 Ecodry 1 and 2 on. Started opening manual valve.

12:20 Manual valve opened fully, T1600 backing valve opened. Started turbos.

12:30 Pressures (mBar):

• TPU1 = 3.0e-5
• TPU2 = 5.1e-6
• TPD1 = 5.1e-6
• TPD2 = 7.5e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Far S2 biased to -130.0V, leak I = 1.52uA. Diode biased to -70.1V, leak I = 0.01uA.

Rate meter ~ 7000Hz. Ladder set to position #4 - alpha source. Rate meter still ~ 7000Hz.

Run # 181128123940

• Run time: 3428s
• Pulser ON, as before
• Alpha-source
• S2 mylar: 0.9um
• DT ~ 22%
• See attached picture 5 for sample Far S2 front strip spectrum

On 28/11/2018:

Performed pulser walkthrough, Run # 181128090835

• Run time: 1986s
• Pulser ON, amplitude changed
• Target: None
• Beam: None
• DT ~ 11%
• See attached picture 1 for sample pulser walkthrough spectrum, ADC 2 channel 3 (ADC 3 in DAQ file browser)

Pulser amplitudes swept through (measured amplitude checked after collecting pulser walkthrough to ensure no additional load was placed on pulser):

After walkthough pulser amplitude setting set back to 70000, all other settings left unchanged

Far S2 and diode biases switched off. Preamp power off. Line valve and FCC valve closed. Turbos off. Manual and T1600 backing valves closed. Ecodry 1 and 2 off. Waited for turbos to spin down.

By 10:20 turbos had finished spinning, vented chamber ready to mount alpha source.

On 27/11/2018:

Run # 181127200709

• Run time: 46329s
• Pulser ON, as before
• No target
• No beam
• Lab background
• DT ~ 12%
• See attached picture 1 for sample far S2 front strip spectrum. See attached picture 2 for diode spectrum.

At 20:00:

Far S2 bias = -130.0V, leak I = 1.52uA. Diode bias = -70.1V, leak I = 0.00uA. Preamps drawing correct current.

Pressures (mBar):

• TPU1 = 7.0e-6
• TPU2 = 1.9e-6
• TPD1 = 1.5e-6
• TPD2 = 1.7e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Rate meter ~ 5000Hz

On 28/11/2018:

At 8:55 Far S2 bias = -130.0V, leak I = 1.67uA. Diode bias = -70.1V, leak I = 0.00uA.

Rate meter ~ 4100Hz

Pressures (mBar):

• TPU1 = 8.5e-7
• TPU2 = 6.3e-7
• TPD1 = 7.5e-7
• TPD2 = 6.5e-7
• CHUP = Sensor Off
• CHDW  No Sensor

Stopped lab background run

On 27/11/2018:

After tuning beam (see previous eLog entry # 64)

Run #181127193908

• Run time: 1589s
• Pulser ON, as before
• Target: CH2 50
• Beam: 1.5MeV 6Li 1+
• See attached picture 1 for sample S2 front strip spectrum. See attached picture 2 for diode spectrum

On 27/11/2018:

Started tuning for 1.5MeV 6Li 1+. Set ladder to position #2 - Blank 10mm. Far S2 iris closed.

Run # 181127151653

• Run time: N/A
• Pulser ON, as before
• Target: Blank 10mm
• Beam: 1.5MeV 6Li 1+

Moved ladder to position #5 - natC III

Run # 181127152055

• Run time: N/A
• Pulser ON, as before
• Target: natC III
• Beam: 1.5MeV 6Li 1+
• DAQ Crashed

Restarted FAIR DAQ

Run # 181127153422

• Run time: N/A
• Pulser ON, as before
• Target: natC III
• Beam: 1.5MeV 6Li 1+
• Run stopped incorrectly by user

Run # 181127153506

• Run time: 489s
• Pulser ON, as before
• Target: natC III
• Beam: 1.5MeV 6Li 1+

Run # 181127155040

• Run time: 187s
• Pulser ON, as above
• Target: natC III
• Beam: 1.5MeV 6Li 1+

Moved ladder to position #3 - CH2 XVI

Run # 181127155607

• Run time: 908s
• Pulser ON, as above
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+
• DT ~ 15%

Struggling to see beam in diode for all of these past runs.

Opened iris to use far S2 as diagnostic tool - beam is stopped in thick CH2 targets so detector is safe even at its small angular coverage (~5 - 15 degrees)

Run # 181127161508

• Run time: 14s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+

No high rate seen

Run # 181127161656

• Run time: 194s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+
• DT ~ 12%

Still struggling to see beam on diode

Found lemo cable used for diode timing between CFD and Logic OR has exposed cabling -> replaced lemo. See attached picture 1 for old lemo.

Run # 181127163416

• Run time: 106s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+

Far iris opened

Run # 181127163848

• Run time: N/A
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+

Realised we were making a mistake when looking at the DAQ spectra. We were looking at ADC 2 (labelled as 3 on DAQ file browser) channel 16 (an S2 back strip) when we should have been looking at ADC 3 (labelled as 4 on DAQ browser) channel 16 for the diode

Closed iris, checked beam current. Using 10mm aperture FCC = 1pA.

Opened iris, moved ladder to position #3 - CH2 XVI

Run # 181127164749

• Run time: 556s
• Pulser ON as before
• Target: CH2 XVI
• Beam: 1.5MeV 6Li 1+

Ready to mount thin CH2 target.

At 16:55: Far S2 bias = -130.0V, leak I = 1.75uA. Diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 9,2e-7
• TPU2 = 3.4e-7
• TPD1 = 6.4e-7
• TPD2 = 6.8e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Switched off detector biases, switched off preamps. Closed FCC valve. Closed line valve. Turbos off. T1600 backing and manual valves closed. Ecodry 1 and 2 off.

Vented chamber. Mounted thin target CH2 50 ~ 50mm from Far S2 - see attached picture 2.

Left 0.9um mylar in front of far S2.

Remounted far S2 and far preamp. With detectors on in air trigger rate ~ 9kHz.

19:00 Ecodry 1 and 2 on. Started opening manual valve.

19:15 pressures below 10 mBar, manual valve fully opened. T1600 backing valve opened. Turbos on.

19:25 Pressures (mBar):

• TPU1 = 3.2e-5
• TPU2 = 8.1e-6
• TPD1 = 6.0e-6
• TPD2 = 8.3e-6
• CHUP = Sensor Off
• CHDW = No Sensor

Far S2 biased to - 130.0V, leak I = 1.52uA. Diode biased to -70.1V, leak I = 0.00uA.

Closed iris, set ladder to position #2 - blank 10mm

See 1 -> 2 pA beam on FCC, opened iris ready for measurement.

On 27/11/2018:

At 8:40 Far S2 bias = -130.0V, leak I = 1.74uA. Diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 8.3e-7
• TPU2 = 3.4e-7
• TPD1 = 6.5e-7
• TPD2 = 6.5e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Preamps still drawing necessary currents.

Stopped overnight run of 3.0MeV 7Be 2+ on CH2 XIX

Checked beam current: FC4 = 2pA.

Moved ladder to position #5 - natC III

Run # 181127085408

• Run time: 627s
• Pulser ON, as before
• Target: natC III
• Beam: 3.0MeV 7Be 2+
• DT ~ 23%
• See attached picture 1 for sample S2 front strip spectrum. See attached picture 2 for diode spectrum.

Moved ladder to position #2 - 10mm aperture

Run # 181127090808

• Run time: 601s
• Pulser ON, as before
• Target: Blank 10mm aperture
• Beam: 3.0MeV 7Be 2+
• DT ~ 10%
• See attached picture 3 for Far S2 innermost strip spectrum.

Moved ladder to position #7 - CH2 XIX

Run # 181127092128

• Run time: 663s
• Pulser ON, as before
• Target: CH2 XIX
• Beam: 3.0MeV 7Be 2+
• DT ~ 10%
• See attached picture 4 for sample S2 front strip spectrum. See attached picture 5 for diode spectrum.

* End of 7Be beam *

On 26/11/2018:

Tuned beam for 3.0MeV 7Be 2+. Far S2 iris was closed during tuning.

After tuning, using 10mm aperture FCC = 5pA, using 3mm aperture FCC = 4pA.

Set ladder to position #7 - CH2 XIX

Run # 181126190248

• Run time: 1298s
• Pulser ON, as before
• Target: CH2 XIX
• Beam: 3.0MeV 7Be 2+

Left beam running and data collecting overnight

Run # 181126192446

• Run time: 47915s
• Pulser ON, as before
• Target: CH2 XIX
• Beam: 3.0MeV 7Be 2+
• See attached picture 1 for sample S2 front strip spectrum. See attached picture 2 for diode spectrum.

On 26/11/2018, after changing the far S2 mylar foil (see previous eLog entry #60):

Checked pulser frequency on oscilloscope: 19.31Hz

Began tuning 3MeV 7Li 2+.

After tuning, FC4 = 1nA. Using 10mm aperture FCC = 313pA. Using 3mm aperture FCC = 250pA.

Ladder set to position #7 - fresh C2 XIX target. Far S2 iris opened.

Run # 181126162248

• Run time: 753s
• Pulser ON, as before
• Target: CH2 XIX
• Beam: 3.0MeV 7Li 2+
• DT ~ 18%

Set ladder to position #5 - natC III

Note: now saving to /Local_Parts/PartODF/

Run # 181126163853

• Run time: 73s
• Pulser ON, as before
• Target: natC III
• Beam: 3.0MeV 7Li 2+
• DT ~ 20%
• Observe 7Li passing through target

Moved ladder to position #2 - blank 10mm aperture

Run # 181126164509

• Run time: 67s
• Pulser ON, as before
• Target: Blank 10mm
• Beam: 3.0MeV 7Li 2+

Still see scattered beam at low S2 strips #'s - see attached picture 1 for spectrum of the innermost S2 strip.

Performed further beam tuning to improve transmission.

After tuning: Using 10mm aperture FCC = 415pA (280 - 420pA). Using 3mm aperture FCC = 290pA.

Moved ladder to position #3 - CH2 XVI. Bombarded target with 3.0MeV 7Li 2+ and checked rate histogram on FAIR DAQ. ADC1 CH24 didn't show higher rates compared to other channels (eg ADC 1 CH10)

Moved ladder to position #7 - CH2 XIX

Run # 181126183711

• Run time: 616s
• Pulser ON, as before
• Target: CH2 XIX
• Beam: 3.0MeV 7Li 2+
• DT ~ 14%
• See attached picture 2 for sample S2 front strip spectrum. See attached picture 3 for diode spectrum.

On 26/11/2018, after 6.0MeV 7Be and 7Li beam measurements:

At 11:15:

Far S2 bias = -130.0V, leak I = 1.60uA. Diode bias = -70.1V, leak I = 0.00uA.

Pressures (mBar):

• TPU1 = 8.5e-7
• TPU2 = 3.1e-7
• TPD1 = 6.2e-7
• TPD2 = 6.3e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Detectors and preamps switched off. Turbos off. Line valve closed. Manual and T1600 backing valves closed. Ecodry 1 and 2 off.

Waited for turbos to spin down.

Opened vent valve at Turbo Entrance 3. The automatic FCC valve immediately closed -> interlock tripped downstream of chamber and stopped turbo at FCC.

With FCC valve closed (allowing the chamber to continue venting) we restarted turbo at FCC -> spun up to operating 1000 Hz.

Once chamber finished venting, the far S2 was removed and its 12um mylar was replaced with 0.9um mylar ready for beam measurements at Elab = 3MeV. See picture 1 for 0.9um mylar mounted in front of far S2.

Far S2 remounted with far iris arm. Far S2 preamp remounted.

Preamp power on, currents drawn are good. Far S2 biased to -130.0V, leak I = 1.53uA. Diode biased to -70V, leak I = 0.00uA.

Noise looked ok. Detector biases off.

12:50 Ecodry 1 and 2 on. Started opening manual valve.

13:05 manual valve opened fully. T1600 valve opened.

13:10 Turbos on, pressures reached ~9e-5 mBar

Far S2 bias = -130.0V, leak I = 1.48uA. Diode bias = -70.1V, leak I = 0.00uA.

Set new RAL thresholds whilst monitoring rate: (counting from left of RAL rack)

• RAL #1 and 2: 20mV
• RAL #3: 15mV
• RAL #4 and 5: 10mV
• RAL #6: 15mV

13:25 Pressures (mBar):

• TPU1 = 1.0e-5
• TPU2 = 2.8e-6
• TPD1 = 2.5e-6
• TPD2 = 3.3e-6
• CHUP = Sensor Off
• CHDW = No Sensor

On 26/11/2018:

The accelerator and chamber setup were still operating after the overnight run.

Far S2 bias = -130V, leak I = 1.59uA. Diode bias = -70.1V, leak I = 0.00uA.

8:35 pressures (mBar):

• TPU1 = 8.6e-7
• TPU2 = 3.1e-7
• TPD1 = 6.1e-7
• TPD2 = 6.3e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Checking for beam-induced background, moved target ladder to position # 2 - blank 10mm aperture

Run # 181126084821

• Run time: 1204s
• Pulser ON, as before
• Target: Blank 10mm
• Beam: 6.0MeV 7Be 2+

Using blank 10mm frame FCC = 6pA

Stopped run - CSSM magnet was switched on halfway through. This this the magnet located immediately downstream of the chamber and we were worried about it affecting the noise. Switched off CSSM magnet.

Run # 181126090936

• Run time: 1239s
• Pulser ON, as before
• Target: Blank 10mm
• Beam: 6.0MeV 7Be 2+
• DT ~ 8%

Moved ladder to position #5 - natC III

Run # 181126093314

• Run time: 1416s
• Pulser ON, as before
• Target: natC III
• Beam: 6.0MeV 7Be 2+
• DT ~ 8%

Moved ladder to position #2 - blank 10mm aperture. Closed far S2 iris and switched beam to 6.0MeV 7Li 2+.

Using 10mm aperture FCC = 360pA. Using 3mm aperture FCC = 300pA.

Moved ladder to position #4 - CH2 XVIII. Opened Far S2 iris.

Run # 181126105357

• Run time: 1383s
• Pulser ON, 25Hz
• Target: CH2 XVIII
• Beam: 6.0MeV 7Li 2+
• DT ~ 12%
• See attached picture 1 for sample Far S2 front strip. See attached picture 2 for diode spectrum.

Ready to replace Far S2 12um mylar with 0.9um mylar protective foil

On 25/11/2018:

The beam was tuned for 6.0MeV 7Be 2+

Using 10mm aperture FCC = 12 pA

Run # 181125121226

• Run time: 7264s
• Pulser ON, as before
• Target: CH2 XVIII
• Beam: 6.0MeV 7Be 2+
• See attached picture 1 for sample spectrum of Far S2 front strip. See attached picture 2 for diode spectrum.

Run # 181125141350

• Run time: 1887s
• Pulser ON, as before
• Target: CH2 XVIII
• Beam: 6.0MeV 7Be 2+

During this run at 14:40 there was a very brief power outage. The run was stopped afterwards.

Check chamber setup:

Far S2 bias = -130.0V, leak I = 1.89uA

Diode bias = -70.1V, leak I = 0.00uA

Pressures (mBar):

• TPU1 = 1.0e-6
• TPU2 = 3.2e-7
• TPD1 = 6.5e-7
• TPD2 = 6.1e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Preamps for Far S2 and diode are still drawing correct currents. The chamber setup appears unaffected by the brief outage.

At this point the pulser was disconnected from the oscilloscope - removing the load on the pulser. We expect the pulser peak position to change as a result.

After the outage we needed to retune beam for 6.0MeV 7Be 2+

Moved target ladder to position #2 - blank 10mm aperture. Had troubles finding beam, moved target to natC III. In diode spectrum we saw beam energies ~ 7-8MeV.

It turned out the bending magnet located right after the ion splutter source needed recalibrating. It was recalibrated using Hydrogen (A=1), Carbon (A=12), and Oxygen (A=16).

During the retuning, the pulser frequency was checked for both the 2.5 and 25Hz settings:

Pulser setting set to 2.5Hz

• Pulser frequency measured internally by scope: 2.095 -> 2.096Hz
• Pulser frequency measured using scopes cursors: 2.092Hz

Pulser setting set back to 25Hz

• Pulser frequency measured internally by scope: 19.29 -> 19.30Hz
• Pulser frequency measured using scopes cursors: 19.38Hz

After recalibrating the bending magnet, we switched beam to 6.0MeV 7Li 2+ to benefit from the higher beam current.

After tuning: FC4 = 1.25nA. Using blank 10mm aperture FCC = 96pA, using blank 3mm aperture FCC = 66pA -> ~70% transmission attained.

Switched beam back to 6.0MeV 7Be 2+

Using 3mm aperture FCC = 7pA.

Opened Far S2 iris (was closed during retuning after power outage), set target ladder to CH2 XVIII

Run # 181125223800

• Run time: 35914s
• Pulser ON, 25Hz
• Target: CH2 XVIII
• Beam: 6.0MeV 7Be 2+
• Left running overnight
• See attached picture 3 for sample spectrum of Far S2 front strip. See attached picture 4 for diode spectrum.

On 25/11/2018:

At 8:45 the pressures read (mBar):

• TPU1 = 1.0e-6
• TPU2 = 3.2e-7
• TPD1 = 6.5e-7
• TPD2 = 6.1e-7
• CHUP = Sensor Off
• CHDW = No Sensor

Biased detectors: Far S2 bias = -130.0V, leak I = 1.80uA. Diode bias = -70.1V, leak I = 0.00uA.

Checked pulser frequency:

• Frequency setting = 25Hz (250Hz max fine gain setting)
• Pulser frequency measured internally by scope: 19.29->19.31Hz
• Pulser frequency measured using cursors on scope: 19.38Hz

Target ladder left in position #2 overnight - 10mm aperture. Far S2 iris also left open overnight.

Checked for beam induced background from beam scattering on aluminium target frame and/or ladder. FC4 ~ 17pA, FCC ~ 6pA

Run # 181125090005

• Run time: 977s
• Pulser ON, as before
• Target: 10mm aperture
• Beam: 4.0MeV 7Be 2+

Tuned beam for 6.0MeV 7Li 2+

After tuning: FC4 = 1.05nA. Using 10mm aperture FCC = 520pA, using 3mm aperture FCC = 460-480pA.

Collected 7Li + p data using old target CH2 XVI (used for 7Be yesterday)

Run # 181125112005

• Run time: 754s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 6.0MeV 7Li 2+
• DT ~ 10%

Run # 181125113257

• Run time: 18s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 6.0MeV 7Li 2+

Moved target ladder to position # 4 - fresh CH2 XVIII

Run # 181125113734

• Run time: 324s
• Pulser ON, as before
• Target: CH2 XVIII
• Beam: 6.0MeV 7Li 2+

See attached picture 1 for a sample spectrum from one of the Far S2 front strips. See attached picture 2 for the diode spectrum.

Moved target ladder to position #5 - natC III

Run # 181125114513

• Run time: 620s
• Pulser ON, as before
• Target: natC III
• Beam: 6.0MeV 7Li 2+

After the previous run, it was discovered the pulser was still being split between the far S2 preamp test input, and the oscilloscope (morning check of pulser frequency). Therefore the pulser had an additional load and we expect a shift in the pulser amplitude compared to runs made yesterday.

Checking for beam induced background, the target ladder was moved to position #2 - blank 10mm aperture

Run # 181125115810

• Run time: 386s
• Pulser ON, as before
• Target: Blank 10mm aluminium frame
• DT ~ 8%
• FCC ~ 400pA

On 24/11/2018:

After the short test with 4.0MeV 7Li (see eLog #55) the beam was tuned for 4.0MeV 7Be 2+.

Run # 181124103943

• Run time: 43s
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+
• Comment: Far S2 iris was closed!

Run # 181124104408

• Run time: 3971s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+

After this run we checked the beam current:

FC4 = 10pA

Using 10mm aperture FCC = 4.5pA, using 3mm aperture FCC = 4.0pA

Attempted to increase beam current by adjusting bending magnet - optimum: 413.30mT

Run # 181124120558

• Run time 7930s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+

See attached picture 1 for a sample spectrum from the S2 front strip. See attached picture 2 for the diode spectrum - the peaks from 7Be and 7Li are visible. Recall the diode has a 0.9um mylar protective foil in front of it.

Run # 181124141834

• Run time: 3362s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+

Further attempts to increase beam current, ioniser increased from 24.0 -> 24.5A. FC4 = 15pA

Run # 181124154345

• Run time: 3609s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+

Checked beam current: using 10mm aperture FCC = 4pA (time: 16:44)

Decreased oven temperature -> FC4 = 16pA

Run # 181124165221

• Run time: 4221s
• Pulser ON, as before
• Target: CH2 XVI
• Beam: 4.0MeV 7Be 2+

Collected background using carbon target:

Run # 181124180623

• Run time: 463s
• Pulser ON, as before
• Target: natC III
• Beam: 4.0MeV 7Be 2+

Beam current seemed unstable, run stopped, no actions taken. FCC ~ 5pA.

Run # 181124182304

• Run time: 3647s
• Pulser ON, as before
• Target: natC III
• Beam: 4.0MeV 7Be 2+

See attached picture 3 for a sample spectrum from the S2 front strip. The spectrum indicates hydrogen contamination is present on the carbon foil. See attached picture 4 for the diode spectrum.

After run: checked beam current. FC4 = 18pA. Using 10mm aperture FCC = 5.5pA.

Leaving for the night:

Far S2 leak I = 1.87uA. Far S2 and diode biases off.

19:25 pressures (mBar):

• TPU1 = 1.4e-6
• TPU2 = 3.7e-7
• TPD1 = 7.0e-7
• TPD2 = 6.6e-7
• CHUP = Sensor Off
• CHDW = No Sensor

On 24/11/2018:

At 8:35 the chamber pressures read (mBar):

• TPU1 = 2.2
• TPU2 = 2.2
• TPD1 = 2.2
• TPD2 = 2.0
• CHUP = Sensor Off
• CHDW = No Sensor

The chamber was vented and the CH2 XV target replaced with new ones.

See picture 1 for target ladder after dismounting - the beam spot from 7Li is clearly visible on CH2 XV.

The target ladder configuration is now:

See picture 2 for the new configuration.

The target ladder was remounted and at 9:15 the chamber pumped down. The far S2 still has the 12um mylar protective foil.

By 9:30 the pressures read (mBar):

• TPU1 = 4.6e-5
• TPU2 = 7.4e-6
• TPD1 = 6.8e-6
• TPD2 = 8.7e-6
• CHUP = Sensor Off
• CHDW = No Sensor

The Far S2 was biased to -130V, leak I = 1.38 uA. The diode biased to -70V, leak I = 0.00uA

A beam of 7Li 2+ 4.0MeV was focused onto the target position.

After focussing, FC4 = 260 pA, FCA = 250 pA. Both of these faraday cups are before the target chamber.

After focussing with the 10mm aperture, FCC = 195 pA. Focussing with the 3mm aperture, FCC = 190 pA. Faraday cup C (FCC) is after the target chamber.

A spectrum was collected for 7Li 4.0MeV

Run # 181124101041

• Run time: 717s
• Pulser ON, 25 Hz, as before
• Target: CH2 XVI
• Beam: 4.0 MeV 7Li 2+
• Trigger rate: 3285/s
• DT ~ 6%

On 23/11/2018:

After the runs with 7Li on CH2 15, we moved the target ladder to position 5: carbon foil #3 (~590 ug/cm^2)

Run # 181123214406

• Run time: 1247
• Pulser ON, same settings as run # 181123130304

Beam intensity = 150pA on FCC with 3mm aperture

For the night we closed the quadrupole and line valves, and switched off the pumps and detectors.

On 23/11/2018:

Tuned beam for 4.0 MeV 7Li, charge state 2+

Measured transmission of beam through FCC using 3 mm and 10 mm size collimators: 66 pA with 10 mm -> 60 pA with 3 mm -> 91% transmission

FC4 = (330 - 263) pA = 127 pA

Set target ladder to position 3 - CH2 target 15 (880 +/- 40 ug/cm^2)

Start run

• Run # 181123130304
• Pulser: 70000 amplitude, x10 attenuation, 25Hz frequency (250Hz minimum fine setting), positive polarity
• Run time ~30 minutes

Start run

• Run # 181123134943
• Pulser: as above
• Run time 588 seconds

Moved to position #2 on target ladder, 10mm collimator. Increasing beam intensity -> have to refocus

Moved ladder to position #1 (3mm collimator). Closed iris. Refocusing.

Beam intensity after refocus: ~140pA with 10mm, ~90pA with 3mm. Trigger rate ~ 5500 counts/s

Moved ladder to position #3: CH2 target 15

Run # 181123142805

• Pulser: as above
• Run time: 1034

We found high rates on ADC 1 -> swapped input cables between ADC 1 and ADC 2 (modules #2 and #3)

Run # 181123144810

• Run time: 417
• Pulser: as above

Set RAL thresholds to 20mV for first 8 modules

Run # 181123150803

• Run time: 398
• Pulser: as above

Did not help with ADC 1 counting less than ADC 2. Swapping ADC 1 with ADC 4.

Run # 181123151711

• Run time: 324
• Pulser: as above

Swapping back ADC 4 -> ADC 1. Found ECL cable between the MALU module corresponding to ADC 1 and OR not plugged in. Trigger rate now 44000. Re-optimising noise.

RAL first 6 modules thresholds set to 30 mV. DT ~ 44%, high trigger rate.

First 3 RAL thresholds set to 35 mV, next 3 RAL thresholds set to 20 mV. Preamp box lid removed.

Run # 181123162236

• Run time: 348
• Pulser OFF

Run # 181123163138

• Run time: 1561
• Pulser: ON, rate: 2.5 Hz, other settings unchanged

Run # 181123165817

• Run time: 3731
• Pulser as previous run

Run # 181123180118

• Run time: 1971
• Pulser ON, as before

Run # 181123183556

• Run time: 1638
• Pulser ON, as before

Checking beam intensity:

• Beam intensity = 197pA in FC4 at 18:34
• Beam intensity = 100 pA (91->105 pA) in FCC at 19:00

Run # 181123191153

• Run time: 7029
• Pulser ON, as before

Checking beam intensity:

• Beam current = 167 pA in FC4 at 21:00
• Beam current = 83 pA in FCC at 21:00

Lowering RAL thresholds:

• RAL #1 and 2 thresholds set to 25mV
• RAL #3 threshold set to 20mV
• RAL #4, 5, and 6 thresholds unchanged at 20mV

Now trigger rate ~ 5kHz, dead time ~ 8 - 10%

Run # 181123212726

• Run time: 807
• Pulser ON, as before
• Target: CH2 XV
• RAL #3 threshold increased to 25mV during this run

After previous run (# 181123212726) pulser frequency setting set to 25Hz, other settings unchanged

On 23/11/2018:

10:15 started pumping down chamber with Ecodry 2

RAL thresholds:

• First 4 RALs = 10mV
• 5th RAL = 17mV
• 6th RAL = 20mV
• 7th and 8th RALs ECL disconnected
• 9th - 16th RALs not in use (no near S2)

10:30 pressures ~ 1mBar, opened T1600 backing valve, Turbos switched on

10:35 pressures (mBar):

• TPU1 = 5.2e-5
• TPU2 = 6.4e-6
• TPD1 = 6.0e-6
• TPD2 = 8.7e-6
• CHUP = 2.3e-5
• CHDW = 5.5e-5

Biased detectors: Far S2 bias = -130V, leak I = 1.54uA. Diode bias = -70V, leak I = 0.02uA.

Replaced diode TFA, now using channel 4 on new TFA. Diode connected to 3rd ADC channel 16 (counting from 0)

Started pulser only run

• Run # 181123111015

Closed far S2 iris (82.5mm actuator setting). Set target ladder to blank 10mm target frame.

Disconnected vacuum gauges located below chamber on same side as target ladder is mounted - noise improved

Started pulser only run

• Run # 181123113237

On 22/11/2018 in the afternoon:

We increased the ADC thresholds to 40 (previously 8).

For an alpha source with pulser connected, the event multiplicity dropped from ~63 to ~10. Dead time ~ 7%

Checking the timing signals for the near S2:

• RAL X channels 0 - 5 bad, 6 and 7 good -> disconnected timing
• RAL U, XII, XIII, R, and S good
• RAL W channels 0 - 5 good, 6 and 7 bad
• RAL Q all bad -> disconnected timing

Started alpha source run with pulser (same pulser settings as run before)

• Run # 181122161955

After run the Far S2 RAL thresholds set to 10mV, the close S2 thresholds set to 50mV

Started alpha source run, no pulser

• Run # 181122170947

Stopped run due to poor alpha rate -> ECL-Nim ribbon cable disconnected.

Checking bias:

• Far S2 bias = -130V, leak I = 1.91uA
• Close S2 bias = -129.9V, leak I = 13.11uA
• diode bias = -70V, leak I = 0uA

Vented chamber and checked 12um mylar foil in front of close S2 - no visual damage. LEft

Close detector changed: S2 2623-26 (505um) replaced with S2 2623-18 (508um). Mounted new S2 in close position with 12um mylar

Removed alpha source - needed by other experiment. Otherwise target ladder configuration is same as eLog entry #47

Checked grounding cables going from preamps to ICU boxes were tightly connected

Attempted to bias close S2 -> no leak current! Left lab for the day.

The next morning (23/11/2018):

We found the BNC - SMC bulkhead connector attached to the near S2 preamp box is missing a pin. We dismounted the near S2.

We observed ~50kHz noise on Far S2, this is removed when we lifted the preamp - ICU box ribbon cables away from the chamber vacuum gauges.

The FAIR DAQ IP address: 192.168.1.90

The data is saved in /Local_Parts/Part0DE/

After each run we should copy the data to the 7Be shift folder: /home/circe/7Be_pp/181122/

We convert the data to a .root file via the command: fair2root ./run#

To convert the data to root we need to use the fairdef.in config file

The target ladder is set for position 7 - the double alpha source.

Looking at the FAIR DAQ, for the Far S2 the first RAL amplifier (XV) shows:

• Alphas at channel 700
• Pulser centroid at channel ~2640, with 9 channel FWHM -> corresponds to 44 keV FWHM at 4.91 keV/channel

The close S2 shows:

• Alphas at channel 700
• Same pulser centroid as far S2, with 6 channel FWHM -> corrsponds to 24 keV FWHM at 4.91 keV/channel

We reenabled the top ICU box channels 0 and 5 (disabled during Feb 2018 shift)

We started an alpha-source run using the 241Am and 239Pu source, type: EA X, product number: 111109-1242002. Photo of source storage case is attached.

Alpha activity at 25/03/2010: 8.153 kBq

We found the following strange behaviour

With DAQ list mode OFF:

• Trigger rate ~2300 - 2700/s
• Event mult ~ 140
• DT~18%

With DAQ list mode ON:

• Trigger rate ~300 - 900/s
• Event mult ~140
• DT ~ 70 - 90%

Currently ADC 2, 3, 4, and 5 are in use by the far and near S2's. ADC 6 and TDC 7 are not currently in use (we will need ADC 6 for the pin diode)

We set the lower threshold for ADC6 and TDC7 to 2046 out of 2047 channels - effectively disabling the two.

Now with list mode ON:

• Trigger rate ~ 1500 - 1700 /s
• Event mult ~ 65 - 70
• DT ~ 30 - 50 %

We restarted the DAQ machine

We started an alpha source run:

• Run number: 181122123034
• DT ~ 7 - 19%
• Trigger rate ~ 700 - 1000/s
• Event mult ~ 63

The PB-4 Pulser Settings are:

• Frequency: 250 Hz
• Delay: 1 us
• Rise Time: 0.1 us
• Fall Time: 100 us
• Reference: INT
• Polarity: +ve
• Amplitude on scope: 260mV
• Attenuation: X10 (X10 switch up, X2, X5, and the other X10 switch are down)

This morning at 8:35am the pressures read (in mBar):

• TPU1 = 2.0e-6
• TPU2 = 4.5e-7
• TPD1 = 8.1e-7
• TPD2 = 7.9e-7
• CHUP = 4.7e-7
• CHDW = 1.1e-5

The detectors were biased. Far S2 leak I = 1.54uA, near S2 leak I = 12.53uA.

It was discovered the ECL-NIM-ECL converter located immediately to the left of the pulser has broken channels - the last 8 channels. Instead of connecting the 32 pin ribbon cable to the input and taking lemo outputs 5 and 13,  we are now connecting two single channel pin cables to inputs 1 and 2, and taking the corresponding lemo outputs.

We found RAL X sometimes doesn't produce a trigger for the pulser.

We replaced RAL I with RAL XIV, RAL XIV is bad.

We replaced RAL XIV with RAL XV,  RAL XV is good.

We finished setting the RAL thresholds.

Today we mounted the far aperture used to control the far iris. No problems were encountered with this.

We mounted the target ladder with the following configuration, see also pictures 1 and 2:

The alpha source is 241Am + 239Pu

We also have mounted the near and far S2's with 12um mylar, and the pin diode with 0.9um mylar.

We only had the far iris arm actuator mounted, because a new iris arm for the near iris mount was being manufactured in the CIRCE workshop.

During ~midday through the early afternoon we found vacuum problems. These were solved by remounting the far chamber lid, and also remounting the far iris arm actuator (This had incorrect length bolts).

The new iris arm for the near S2 came back from the workshop, unfortunately we still could not mount it. We decided against mounting this iris arm, and instead mount the near S2 with the iris completely open and the 12um mylar protective foil.

We will only be able to measure at Elab = 4MeV, becasue at Elab = 6MeV the 7Li penetrates through 12um mylar and so we would be risking the near S2 during beam tuning (not an option!).

We mounted the near S2 with iris open and 12um mylar foil. The far S2 was already mounted with 12um foil and the iris arm aperture. The far S2 iris was opened fully (setting 1.5mm on actuator) ready for pumping and alpha source measurement.

At 16:50 we started the Ecodry 1 and 2 pumps and opened the manual gate valve. By 16:55 we fully opened the gate valve and also the T1600 backing valve, allowing both ecodrys to pump on the chamber. We then switched on the turbos.

By 17:20 the pressures read (in mBar):

• TPU1 = 3.4e-5
• TPU2 = 3.3e-6
• TPD1 = 3.4e-6
• TPD2 = 4.1e-6
• CHUP = 1.2e-5
• CHDW = 2.8e-5

During pump down we mounted the preamp boxes with daisy chained BNC cables.

We applied preamp power, correct currents drawn: ~1.5A for +ve and ~500mA for -ve

Far S2 biased to -130V, leak I = 1.46uA. Near S2 biased to -130V, leak I = 2.48uA.

Checking for noise, we see the following RMS noise in the RAL amps:

Diode biased to -70V, leak I = 0.02uA

We tested for ground loops - no obvious loops found for either S2 preamp

We connected the RAL amps to the FAIR DAQ, and started an alpha source run with pulser. The dead time was excessively high, ~90%

We started adjusting RAL thresholds up to RAL S, then we called it a day.

The Far S2 leak I = 1.4 uA, near S2 leak I = 3.3 uA.

We unbiased the detectors, switched off the NIM, CAMAC, and RAL crates, and also switched off the preamp power. We didn't wanted anything damaged from potential overnight thunderstorms.

At 20:35 the pressures read (in mBar):

• TPU1 = 6.3e-6
• TPU2 = 8.0e-7
• TPD1 = 1.2e-6
• TPD2 = 1.2e-6
• CHUP = 6.2e-6
• CHDW = 1.4e-5

On 20/11/2018:

After the electronics tests in air (see eLog entry #44) we started to setup the chamber for vacuum tests with an alpha source.

We started mounting the aperture used for controlling the near iris arm, however we encountered a problem. The iris arm got stuck and could not move in either direction (into or out of the chamber)

We dismounted both preamps. After bending the near iris arm's hook we managed to dismount the chambers central lid.

Before doing anything else, we dismounted the near S2 and 12um mylar foil.

A new iris arm for the near iris needs to be manufactured by the workshop in CIRCE. The workshop was closed for the end of the day, so we also stopped for the day.

On 20/11/2018:

At 9:00 we walked into the lab, David R reported he found all the pumps OFF. A thunderstorm occurred overnight causing a power outage.

Last night we had switched off the electronics (Preamp power, RAL amp rack, and NIM bin).

This morning we determined everything was ok to switch on.

Using eLog entries #26 and #27 as reference we mounted the following detectors and foils:

• Far S2: 2323-18, 12um mylar
• Near S2: 2623-26, 12um mylar
• Silicon pin diode: 0.9um mylar

The pin diode used in previous tests had something deposited (fingerprint?) on the crystal, so we replaced this with a new clean diode.

We mounted the detectors and foils inside the chamber, the target ladder was kept in its configuration with all blank frames (see eLog entry # 41). See attached picture 1 for the 12um mylar mounted in front of the far S2.

We mounted preamp I on the near position and preamp II on the far position, as will be used during the measurement.

We sealed the chamber to ensure it was light tight.

We applied pramp power, expected currents were drawn.

With no S2 bias we see high noise on the majority of the RAL amplifiers for both preamps I and II. We switched off the lab lighting and found the chamber was indeed light tight - there were no observable changes in noise.

We discovered CH2 of the Silena HV module does not supply bias.

We applied -10V bias to both S2's. The far S2 is biased using CH1 and the near S2 is biased using CH4 of the HV module. The leakage currents read: Far S2 = 0.35uA, Near S2 = 1.81uA.

With bias RAL X CH 0 baseline RMS noise ~ 55mV.

We biased the pin diode with its operating -70V using CH3 of the HV module, leak I = 0.01uA.

We decided to switch off all biases and prepare for tests under vacuum with an alpha source.

CH1 and 4 of the HV module were set to -130V ready for the S2's

On 19/11/2018:

During the vacuum test - see eLog entry #43 we performed noise tests on the preamplifiers with no S2 detector connected

First we performed a "tabletop" test - the preamplifiers were not connected to the chamber.

Preamp I for the near S2 is connected to RAL modules (reading left to right): X, XII, XIII, R, S, Q, U, and W, via long (~5m) preamp - ICU cables 13, 14, 15, and 16

Preamp II for the far S2 is connected to RAL modules (reading left to right): I, II, XI, IV, V, VI, VII, VIII, via long (~5m) preamp - ICU cables 0, 1, 2, and 3

We powered preamps I and II with + and - 15V. The power supply shows the correct currents drawn: ~1.5A for +ve and ~0.75A for -ve

We found our test 16 pin cables #45 had a dead channel 0, we switched to cable #46 which shows all 8 channels working.

We found the following dead channels on the RAL modules:

We mounted preamps I and II to the top of the chamber. We mounted preamp I on the far S2 mount and preamp II on the near S2 mount, however we were not connecting to the S2's and so continued with the electronics tests.

Now we saw the following dead channels on the RAL modules:

We checked the signal to noise ratio for RAL X CH0:

The input pulser amplitude = 50mV, the RAL analogue amplitude = 950 mV, the RMS noise = 40mV. The S/N ~4.2%.

We stopped tests for the day.

On 19/11/2018:

We mounted the following in the chamber:

• Iris frames - no S2 detectors or mylar
• Si pin diode mount with 0.9um mylar - no diode
• Target ladder with blank frames - same configuration as elog entry #41

At 15:20 we started roughing pumps Ecodry 1 and 2. We opened the manual gate valve followed by the T1600 valve.

After reaching ~10^-2 mBar we started the following turbos:

• Up 1
• Up 2
• Down 1
• Down 2
• T1600
• Entrance 3
• CSSM

By 15:30 the CSSM turbo had reached 56 krpm operating speed and the Up and Down turbos had reached 833 Hz operating speed.

At 19:51 just before we left the lab the pressures read, in mBar:

• TPU1 = 3.7e-6
• TPU2 = 6.9e-7
• TPD1 = 1.0e-6
• TPD2 = 1.2e-6
• CHUP = 6.0e-6
• CHDW = 1.4e-5

On 19/11/2018:

During the target ladder calibration (see elog entry #41) we also replaced the collimator (thickness ~24mm, diameter 3mm) located immediately upstream from the target ladder - that is between the upstream and central sections of the chamber. We mounted an aluminium collimator (thickness ~1mm, diameter 5mm). See attached picture 1.

Using the same telescopic sight as that used for the target ladder calibration, we aligned the 5mm collimator with the beam axis.

On 19/11/2018:

There were three CH2 targets already mounted on the target frame, CH2 III, IV, and a damaged target. We dismounted these.

We noticed these previous target were mounted on the incorrect side of the target ladder, resulting in them being offset upstream from the central axis of the target ladder. This means for the previous tests in February and April 2018 the targets were mounted 3mm (target ladder thickness) upstream from the central position of the ladder.

We mounted blank 10 and 3mm target frames onto the target ladder in the correct centralised position, see attached pictures 1 and 2.

We performed the target ladder calibration using a downstream telescopic sight. The calibration is in agreement with the previous February 2018 calibration.

See attached picture 3 for the calibrated positions, this table is located on the magnet downstream of the chamber.

See attached for Electronics Channel Map spreadsheet.

This is valid for the February 2018 Beamtime; it maps out the Far S2 Strips onto the ADC channels

A map should be produced and updated for each beamtime to ensure S2 Strip -> ADC Channel is correctly documented.

Date: 07/04/2018

Began dismounting detectors:

• All detectors powered off
• Closed line and quadrupole valves
• Preamp power off
• Stopped turbos
• Closed manual gate valve and T1600 Backing valve
• Stopped Ecodry 1 and 2 roughing pumps
• Switched off CAMAC and RAL electronic crates
• FC - 0 suppression voltage switched off (was set to -360V for beam measurements)
• Switched off both NIM crates

After venting the chamber I dismounted both S2 detectors and the 12um mylar in front of each detector

I also dismounted the diode from the chamber, but left the 0.9um mylar glued onto the 4mm diameter metal collimator

I left the target ladder in the chamber

I remounted the central and downstream lids onto the chamber, the diode mount with mylar was left mounted on the central lid

We performed a general cleanup around the lab of the tools used during this shift

At 19:30 we left the lab ^_^

Date: 07/04/2018

FC - 4 = 410 - 260 = 150 pA

We moved the target ladder to position V (35.022mm) - CH2 Target IV

At 15:09 we started the DAQ for 5.0 MeV 7Be in 2+ charge state bombarding CH2 IV

• DT = 0%
• Trigger rate ~ 10Hz
• Event mult = 69.7
• Save name recorded on paper logbook as 180407111531 -> same as save name used for 7Li -> emailed Raffaele to check whether there are other saves starting with 180407......

At 16:39 the DAQ was stopped, RT = 01:29:07, # good events = 68068

Checked beam current due to low trigger rate, FC-4 = 405 - 260 = 155 pA

Central and downstream irises closed, target ladder set to position VII - 3mm collimator

FC - E1 = 63 - 5 = 58 pA, Transmission ~ 33%

Stopped beam, Time ~ 17:00, decided to stop and dismount detectors

17:00 pressures read:

• TPU1 = 2.2e-6 mBar
• TPU2 = 8.2e-7 mBar
• TPD1 = 1.3e-6 mBar
• TPD2 = 1.5e-6 mBar
• CHUP = 1.0e-5 mBar
• CHDW = 2.7e-5 mBar

Detector status:

• Central S2 bias = -129.9V, leak I = 18.71uA
• diode bias = -70.1V, leak I = 0.00uA
• Downstream S2 bias = -130.1V, leak I = 2.84uA

Date: 07/04/2018

To run the measurement we:

• Opened the central iris (actuator setting = 14.0mm)
• Opened the downstream iris (actuator setting = 1.5mm)
• Set the target ladder to position IV (50.015mm)- CH2 Target III

At 14:40 we started the DAQ for 5.0MeV 7Be in the 2+ charge state on CH2 Target III

• DT = 0%
• Trigger rate ~ 10Hz
• Event mult = 71.2
• Save name: 180407134535

At 15:04 we stopped the DAQ

• The proton spectrum seems very thin
• Decided to change to fresh CH2 target IV

Date: 07/04/2018

We changed to cathod 23 - 7Be

For beam tuning we:

• Closed downstream iris (actuator = 82.5mm)
• Closed central iris (actuator = 85.5mm)
• Set target ladder to position I (95.010mm) - 3mm collimator

We found the cathode wheel could no longer be turned remotely, instead Lucio rotated the wheel by hand to cathode 23. We had low beam current at the cathode.

Lucio called Raffaele to confirm the cathode number used yesterday (eLog entry #33)

• Cathode 23 is new -> still has copper on front of cathode which is removed during cesium sputtering -> process takes 2-3 hours
• Instead we moved to cathode 19 - 7Be. Thiis is the cathode used for 7Be yesterday

We decided that when noting faraday cup currents we should also record the offset as well. Previously I was recording the measured minus offset value.

After tuning, and setting the CSSM magnet to 918.3 mT:

• FC - 4 = 410 - 260 = 150 pA (drifted from 450 - 260 = 190 pA)
• FC - 0 = 92 - 0 = 92 pA (drifted from 107 - 0 = 107 pA)
• FC - E1 = 50 - 5 = 45 pA

We felt ready to start a measurement with 7Be

Date: 07/04/2018

At 12:10 we started the DAQ for 5.0 MeV 7Li in 2+ charge state bombarding CH2 Target III

• Save name: RData_1/180407111531
• DT = 0%
• Trigger rate ~ 30 Hz
• Event mult = 77.5

At 12:31 we briefly stopped the beam to check the beam current, FC - 4 = 200 pA

At 13:30 we stopped data aquisition, # good events = 735088. See attached for example spectra of the Central S2 front and back strips, downstream S2 front strips, and the diode monitor.

At 13:32 the pressures read:

• TPU1 = 2.1e-6 mBar
• TPU2 = 9.0e-7 mBar
• TPD1 = 1.4e-6 mBar
• TPD2 = 1.7e-6 mBar
• CHUP = 1.1e-5 mBar
• CHDW = 1.3e-5 mBar

The detectors status:

• Central S2 bias = -129.9V, leak I = 17.90uA
• diode bias = -70.1V, leak I = 0.00uA
• Downstream bias = -130.0V, leak I = 2.59uA

Date: 07/04/2018 (Last day of April shift)

9:55 pressures read: CHUP = 1.3e-5 mBar, CHDW = 3.5 e-5 mBar

I noticed the preamp power (+/- 15V) was left on overnight. The +15V still draws 1.5A and -15V draws ~600mA as expected. During this shift no noticeable change in the currents drawn was observed.

We biased the detectors:

• Central S2 bias = -129,9V, leak I = 17.42 uA (Perhaps this has stabilised to a new value?)
• diode bias = -70.0V, leak I = 0.01uA
• Downstream S2 bias = -130.0V, leak I = 2.38 uA

We decided to adjust the RAL amplifier thresholds for the downstream S2, whilst looking at the analogue and timing outputs on an oscilloscope.

RAL I threshold increased from 15mV to 130mV.

We then struggled to see timing signals from the next 3 RALS in the rack (RAL II, RAL XI, and RAL IV).

The ribbon cables 8,9,10, and 11 connected between the RAL ECL outputs and the Lecroy MALU 4532 modules where tested using the working RAL I ECL output. It was discovered that cables 8 and 9 work, whereas cables 10 and 11 show no signals (note: cables 8,9,10, and 11 merge from 2X8 into 16 channels) . However, even if we plug the working cable 8A into RAL II, XI, or IV we see no OR signals on the oscilloscope, even with RAL threshold setting set to 15mV.

We decided that since this is the last day, and the central detector showed no problems yesterday afternoon, to only incorporate RAL I (first 8 channels on downstream S2) into the DAQ setup.

This problem with the downstream S2 cabling should be addressed at the very beginning of the next shifts, I suspect the problem lies with the vacuum feedthrough -> preamp cable. The cable was removed after the Feb 2018 shifts to add copper tape and its possible that out of the three we have one is damaged. The third (spare) cable is not yet wrapped in copper tape, this will be brought back to Edinburgh after these shifts to apply the tape.

The DAQ OR now comes from:

• RAL I (downstream S2)
• RAL X -> "W" (central S2)
• diode monitor

The analogue output of RAL 1 was sent to the first 8 channels of ADC 1 (module 2)

The RAL X -> "R" go to ADC 3 (module 4) via ribbon cables 12 and 13 and RAL "S" -> "W" go to ADC 4 (module 5) via ribbon cables 14 and 15

The diodes analogue output still goes to ADC 5 (module 6) channel 31, the same case as the Feb 2018 shift

We tried starting the DAQ with no beam, however it gave the error message: Timeout: Performing automatic clear

• After 5 minutes it did not clear, nor give the user control over the start/stop of the DAQ
• We logged into the FAIR console with username root and the password, then ran "reboot -ah" to reboot the FAIR DAQ machine located next to the electronics racks
• We then restarted the FAIR DAQ monitor in the control room
• After rebooting both machines we confirmed the FAIR DAQ machine was on with no error
• We logged back onto the FAIR DAQ monitor in the control room -> needed to use shift+7 to produce the & symbol for the password
• The DAQ is now working

Since we rebooted the DAQ we had to reset parameters for the ADCs:

• RTP (Rise Time Protection) was set to 9 for all ADCs
• The faulty ADC 2 (module 3) lower threshold was set to 2046 (out of 2047)
• The TDC lower threshold was also set to 2046 (out of 2047)
• ADC 1, 3, 4, and 5 (modules 2, 4, 5, and 6) lower thresholds set to 8

We started tuning the accelerator ready for a measurement. We decided to first tune using the 7Li beam from a 7LiO2 cathode, however we realised this was not recorded yesterday. The cathode used should always be recorded in the eLog from now on.

We set the cathode to position 9 - the second 7LiO2 option

Before tuning we:

• Closed the central iris (actuator setting = 85.5 mm)
• Closed the downstream iris (actuator setting = 82.5 mm)
• Set target ladder to position I (95.010mm) - the 3mm collimator
• Opened the line valve
• Decreased the pulser rate from 10 to 2 Hz

With no beam the DAQ reads:

• DT = 0%
• Trigger rate = 25Hz
• Event mult = 72.6

After tuning, including adjusting the steering magnet, faraday cups read:

• FC - 4 = 50 pA
• FC - 0 = 23 pA
• FC - E1 = 16 pA --> 70% transmission

The High Energy slits were left at 1mm for the Up, Down, Right, and Left

We then prepared for the target measurement by:

• Opening the central iris (Actuator = 14.0mm)
• Opening the downstream iris (Actuator = 1.5mm)
• Target ladder set to position IV (50.015mm) - CH2 Target III
• Lowering the pulse height from 1.0 to 0.5 V to lower it to ~ the center of the ADC front strips spectra

We tried running 7Li beam on target, but saw a very low trigger rate in the DAQ of ~ 20Hz. We stopped the beam and Lucio tried increasing current by increasing the Source Heater temperature to ~ 81 degrees centigrade.

At 12:09 FC - 4 = 100pA. We decided to run some 7Li beam whilst the source was heating up -> it will need to run hotter for 7Be anyway.

Date: 06/04/2018

Before starting this beam test we lowered the channel thresholds on ADC 3 and 4 (modules 4 and 5) from 40 to 8

The diode Ortec 571 settings are:

• Fine gain = MAX
• Course gain = 200
• Shaping Time = 0.5us

The diode Delay Amp 1457 settings are:

• Delay = 1us
• Polarity = POS
• Range = 10V

The diode quad CFD (channel 4) threshold = 196 mV

The PB-5 Pulse Generator settings are:

• Fall Time = 100us
• Rate = 10Hz
• Delay = 250 ns
• Ampl = 1V
• Pol = POS
• Pulse Top = Tail
• Atten = 1X
• Clamp = OFF

(Make sure PB-5 = ON to output pulses)

At 19:14 we started the DAQ for 5.0 MeV 7Be at charge state 2+ on target CH2 III

• Dead time = 5%
• Trigger rate ~ 1.8kHz
• Event mult ~ 22.1
• Save name = RData_1/180406181929

At 19:30 we stopped the DAQ, Real time = 00:15:53, dead time = 5%, # good events = 1936195

See attached images for an example back strip and front strip of the central S2, and also for the diode spectrum

Before finishing for the day we decided to once again try to incorporate the downstream S2 into the DAQ setup, because this should have better angular resolution than the central S2

We opened the downstream iris (actuator setting = 1.5mm)

We plugged in RAL I, II, XI, and IV into ADC 1 (module 2) channels 0 ->31, these are the first 32 channels of the downstream S2 preamp output

Even with no beam the DAQ DT = 92% with event mult = 52.0 --> still have a noise problem with the downstream S2

At 19:41 the pressures read:

• TPU1 = 3.3e-6 mBar
• TPU2 = 9.6e-7 mBar
• TPD1 = 1.5e-6 mBar
• TPD2 = 1.7e-6 mBar
• CHUP = 1.0e-5 mBar
• CHDW = 2.7e-5 mBar

The detector biases were:

• Central S2 bias = -129.9V, leak I = 18.39 uA
• diode bias = -70.1V, leak I = 0.00uA
• Downstream S2 bias = -130.1V, leak I = 2.78uA

We called it a day and at 19:45 the detectors were switched off and the line valve closed for the night

Date: 06/04/2018 (after 16:40)

We powered the preamps for the two S2 detectors and the diode.

We biased the detectors:

• Downstream S2 bias = -130.1V, leak I = 2.18uA
• Central S2 bias = -129.9V, leak I =16.71 uA
• diode bias = -70.1V, leak I = 0.01uA

The target ladder was set to position II (No target/frame).The downstream iris was closed to 18mm diameter (actuator setting = 82.5mm). The central iris was closed to 18mm diameter (actuator setting = 85.5mm)

We were ready to begin beam tuning with 7Li.

With no beam, DAQ DT = 2%, trigger rate ~ 800Hz, event mult = 3.6. The DAQ OR is from the central S2 and diode.

During the tuning we had a problem with the CSSM valve -> this is needed to operate the CSSM ERNA magnet for bending the beam into the electron suppressed Faraday cup FC-E1, located downstream from the chamber.

Raffaele fixed this by using an older version of the CSSM magnet labview software.

During tuning we cut the beam using the High Energy slits, the final slit positions were 1mm for the Up, Down, Right, and Left

After tuning with no target frame in the beam axis, we had: FC-4 = 138 pA and FC-E1 = 120 pA, Total transmission = 87%

We set the target ladder to position IV, target CH2 III. The central iris was opened (central actuator = 14.0mm).

At 17:50 we started the DAQ for 5.0MeV 7Li 2+ on target CH2 III. The beam current on FC-0 (immediately before chamber) was 118 pA.

• DT = 18%
• Save name: 180406165546

We saw no signal on the diode monitor, however we saw signals on the central S2, during this run we were adjusting the diode monitor CFD threshold to try and see coincidences with the diodes delayed analogue output on an oscilloscope. So this run is invalid for the diode spectrum,

At 18:40 the DAQ was stopped, run time = 00:47:16

We decided to try adjusting the diode analogue gain on the Ortec 571 amplifier

At 18:40 we restarted the DAQ, again for 5.0MeV 7Li on target CH2 III

• Save name: RData_1/180406174522
• In February 2018 the diode course gain = 50, which corresponded to channel 1000 when no mylar was placed in front of the diode. Now we have 0.9um thick (nominal) mylar in front of the diode.
• During this run we increased the course gain of Ortec 571 to 200
• The delay amplifier was adjusted from 1us to 1.5us, however we saw no difference in the diode spectrum, so this was set back to its original value of 1us

We decided to change over to 7Be beam

Date: 06/04/2018

We connected the analogue signals of RAL X, XII, XIII, and "R" to the 3rd ADC (Module 4)

We connected the analogue signals of RAL "S", "Q", "u", and "w" to the 4th ADC (Module 5)

We set the DAQ or to come from the central S2 and the diode monitor. The downstream S2 was not connected to the DAQ

At 15:14 we started the DAQ, a message appeared: Performing Automatic Clear. After a few seconds this message disappeared

At 15:15 we restarted the DAQ for a 15 minute alpha calibration, 241Am + 239Pu alpha source facing downstream, save name: RData_1/180406142007

The dead time = 3%, trigger rate ~ 1100Hz, Even mult = 5.5

At 15:31 the DAQ stopped, # good events = 1278692

The pressures in the chamber were:

• TPU1 = 3.0e-6 mBar
• TPU2 = 8.2e-7 mBar
• TPD1 = 1.6e-6 mBar
• TPD2 = 1.7e-6 mBar
• CHUP = 1.0e-5 mBar
• CHDW = 2.8e-5 mBar

The detector bias and leak I were:

• Downstream S2 bias = -130.1V, leak I = 2.53 uA
• Central S2 bias = -129.9V, leak I = 16.53 uA
• diode bias = -70.1V, leak I = 0.00 uA

Jeremias needed the alpha source, so after this run we vented the chamber. The detectors and preamps were switched off before starting the venting procedure.

At 16:15 Raffaele and Jeremias removed the target ladder and dismounted the alpha source from position VII. No other changes were made to the ladder.

The ladder was remounted and at 16:19 we started roughing down the chamber. At 16:29 the turbos were started.

At 16:40 the pressures read:

• TPU1 = 1.8e-5 mBar
• TPU2 = 3.8e-6 mBar
• TPD1 = 4.0e-6 mBar
• TPD2 = 5.6e-6 mBar
• CHUP = 1.9e-5 mBar
• CHDW = 5.1e-5 mBar

We were ready to repower the detectors and attempt to run beam on target.

Today we started by mounting the central and downstream preamp box lids.

The pumps were left running overnight, at 9:06 CHUP = 2.1e-5mBar and CHDW = 5.8e-5mBar.

We biased the detectors

• central S2 bias = -129.9V, leak I = 8.09uA
• diode bias = -70.0V, leak I = 0.01uA
• downstream S2 bias = -130.0V, leak I = 1.66uA

The DAQ OR is all 3 detectors, DAQ DT = 82% and trigger rate ~ 6kHz. So the preamp lids made little difference. We saw particularly high rate in ADC 2 channels 1->4, 6 and 7, ADC 4 channels 6 and 31 (both of these are the downstream S2, ADC 5 channels 4 and 5 (central S2), and ADC 6 channels 1->7 (central S2) and 31 (diode)

Decided to ensure copper taped cable is isolated from preamp lid. I cut two sheets of plastic ~ 31 X 19cm and (after powering down the detectors and preamps) placed these between the copper taped preamp - feedthrough cable and the preamp box lid, for both preamp boxes.

Now when the DAQ is triggered from all 3 detectors DAQ DT = 7%, trigger rate ~ 2600Hz, event mult = 49.7

I saw ADC 3 (the "TDC-like" module) was not disabled, i set its ADC threshold to 2046 (out of 2047 channels).

I opened the irises in front of both S2s and moved the target ladder to position VII - alpha source facing downstream.

Now DAQ DT = 7%, trigger rate ~4100Hz, event mult = 18.6

I reset all of the RAL thresholds back to 15mV, I also disconnected the 2nd ECL-NIM converter channel 13 from the Lecroy quad coincidence module because the last 16 channels werent being used for the DAQ trigger anyway.

DAQ DT rose to 85% and trigger rate 32kHz, event mult = 11.8.

ADC 2 channels 1->4, 6, and 7, and ADC 4 channels 30 and 31 still show high rates. Disconnected RAL I and RAL VIII analogue and ECL outputs to remove these.

Now DAQ DT = 22% and trigger rate 8.5kHz, still see a high rate for the diode in ADC 6 CH 31

I tried plugging in the pulser to the diode preamp, pulser setting 0.3V. Ultimately after checking DAQ rate and signals on oscilloscope I raised the diode CFD threshold from 200 to 226mV and settled on this new value.

I decided to keep the diodes analogue delay set to 1us (same used in Feb 2018)

I realised I do need the 2nd ECL-NIM convertor channel 13 in the DAQ OR, because otherwise i could not trigger ADC 6 channels 0->31. This was now remedied

So, the DAQ trigger OR was from RAL II -> VII (downstream S2), RAL X -> "Q" (central S2) and the diode

At 12:03 we started data collection for a 15 minute alpha spectrum, save name  = 180406110805

DT = 78%, trigger rate = 10kHz, event mult = 12.5. DT had dropped to ~ 50Hz during this run. Still saw high rate in ADC 6 channels 1->7 and 31

I was unable to see alpha peaks with good statistics for the downstream S2

At 12:35 I started a 30 minute alpha spectru, save name: 180406114011. DT ~ 73%, trigger rate ~ 9.6kHz

I noticed the central detector leakage current had risen to 10.01uA (bias -129.9V). The diode leak I was still 0.00uA and the downstream S2 leak I was still 2.21uA

When the downstream S2 was connected to the DAQ OR and ADCs a high dead time is seen. Because of this we decided to try and collect some beam data with the central S2.

On 05/04/18, after eLog #28

After the alpha calibrationrun Raffaele arrived and started beam tuning for 7Li 2+ at 5.0MeV using a LiO molecular source

We set the target ladder to position II (80.024 mm) - no target frame or target

Set downstream sperture to 82.5mm and central aperture to 85.5mm (iris diameter ~ 18mm)

Raffaele was struggling with tuning on accelerator end of beamline - decided to perform a pulser walkthrough

16:02 started DAQ for pulser walthrough, save name: 180405150720

Voltages covered: (Pulser amplitude setting)

• 1.4V
• 1.2V
• 1.0V
• 0.8V
• 0.6V
• 0.4V
• 0.2V

Note: pulser is daisy chained between both S2 preamp boxes (NOT diode preamp)

16:56 DAQ stopped, RT = 00:54:05, DT = 67%, Trigger Rate ~ 2kHz, Event mult = 53.1

At 16:57 the pressures read:

• TPU1 = 6.2e-6 mBar
• TPU2 = 9.1e-7 mBar
• TPD1 = 1.7e-6 mBar
• TPD2 = 1.7e-6 mBar
• CHUP = 9.4e-6 mBar
• CHDW = 2.5e-5 mBar

Checked detectors:

• Central S2 bias = -130.0V, leak I = 8.23 uA
• Diode bias = -70.1V, leak I = 0.00uA
• Downstream S2 bias = -130.1V, leak I = 2.44 uA

We opened the line valve, with no beam DAQ reads: DT = 8%, Trigger rate ~ 3400 Hz, event mult = 52.9

Beam tuning was performed with no target frame in the beam axis, beam voltage = 2.1358 MV

We had 1.2nA in FC 4, we supplied -400V to FC-E0 (FC immediately before chamber) for electron suppression

FC - 0 = 1.8nA (unsuppressed immediately after chamber)

We moved the target ladder to position I (3mm collimator)

FC-0 = 600pA

We need to use the ERNA magnet to bend the bean into FC-45 located after the chamber, this faraday cup is suppressed

CSSM magnet ON = 906.13mT, we noticed this section of the beamline needed pumping, switched on pump at 17:45

Received email from Tom D regarding noise, he suggested a few checks:

• Try changing preamp - feedthrough cable (currently have one spare which is wrapped in Al foil instead of copper tape - not ideal)
• Feedthrough - preamp cable drain wire should be connected to PCB at one end and the other left floating (both are attached to PCB at this time)
• Try isolating feedthrough - preamp cable from preamp lid - it may be touching

At 18:00 Raffaele needed to leave the lab, Jeremias could stay until 20:00, we decided to try and address the noise issue further

I switched off the detectors and preamp power, I removed the downstream preamp box lid and disconnected one end of the feedthrough - preamp drain wire (the end where the first 32 channels are connected on the PCB - connector P1)

I remounted the downstream preamp box lid.

The DAQ shows DT = 8% with 3kHz trigger rate.

To check the effect from the central S2, I tried setting the DAQ OR to only come from the central S2 and diode - I realised I could no longer see the pulser peak in the central S2 -> suggested central S2 trigger not working

I changed the cable between the 3rd and 4th MALU 4532 modules and the respective ECL-NIM converter -> now see triggers -> DAQ gives DT = 51% and trigger rate ~ 5.6kHz, but see pulser peaks in ADC modules 5 and 6

I considered only the downstream S2, setting pulser to 1.0V, RAL 1 CH1 amplifies this to ~5.5V with ~20mV noise.

Setting the DAQ OR to only come from this detector, the DAQ DT = 10% and trigger rate = 10Hz, event mult = 133.2. So it seems making one of the drain wires loose had a big effect on the noise.I decided to make the same change for the central preamp.

After switching off the detectors and preamp, I opened up the central preamp box and left one end of the drain wire on the preamp - feedthrough cable hangng loose. This is the same end as the one chosen for the downstream preamp.

Leaving the central preamp lid off, I reapplied preamp power and rebiased the detectors

• central S2 bias = -130.0V, leak I = 8.10uA
• diode bias = -70.0V, leak I = 0.01uA
• downstream S2 bias = -130.1V, leak I = 2.27uA

Checking RAL X CH1 (central S2) amplifiedoutput: 1.0V pulser output is amplified to ~5.5V with 50mV noise. Note the preamp box lid is off, so this looks promising.

I set the DAQ OR trigger to come only from the central S2, DT = 91%, trigger rate ~ 7kHz. High rate seen in ADC 6 channels 1->7 and channel 31

Changed DAQ OR to come from all 3 detectors, DAQ DT = 93% with trigger rate = 6700Hz, still see high rate in ADC6 channels 1-> 7 and channel 31

The time was 20:00 so we stopped for the day, it looks like the downstream S2 electronics is working fine, will check effect of mounting central preamp lid back tomorrow

All detector biases ramped down to 0V, preamp power off

On 05/04/18:

At 9:00 the pressures read ~10mBar inside the chamber (static vacuum). We began venting the chamber.

During venting the cable daisy chain on top of the preamp boxes was removed, the downstream preamp box was removed. It was decided to also removed the central preamp box and its respective spacer box to avoid any collisions when removed the downstream lid.

By 9:20 the chamber was vented. The downstream aperture was removed. The downstream lid was removed, the S2-> vacuum feedthrough cable was changed.

The downstream S2 was remounted into the chamber, and the downstream aperture was remounted onto the chamber collar.

During this process the 4mm diameter collimator for the diode was ready, we decided to also mount this in front of the diode since the chamber was already vented.

The central aperture was removed and the central lid was then removed. The 4mm collimator with 0.9um mylar was installed in from of the diode. The 0.9um mylar was held in place on the collimator using an epoxy.

The central lid was reinstalled, followed by the central aperture on the collar.

The downstream aperture was set to 1.5mm, and the central aperture was set to 14.0mm, opening the irises ready for pumping.

At 10:45 Ecodry 1 and 2 were switched on, the gate valve was cracked open. During roughing the downstream preamp box was mounted followed by the central preamp box.

At 11:03 the T1600 Backing valve was opened and chamber pressures read ~1.0e-1mBar. The 7 turbos were started. (Turbos Up 1 and 2, Turbos Down 1 and 2, Turbo Entrance 3, Turbo CSSM, and T1600)

The +15V, -15V, +ve test, and HV bias cables were reconnected to the central and downstream S2 preamp boxes, and also the diode preamp.

Preamp power was applied, +15V draws 1.5A and -15V draws ~0.6A as expected.

At 11:15 CHUP = 2.6e-5mBar, CHDW = 6.8e-5mBar. Central S2 bias ramped to -130.0V, leak I = 3.51 uA. With the preamp lid off a 0.1V pulser on RAL X CH 1 produced a 1.5V amplified signal with ~200mV noise.

I recollected the bias vs leak I curve for the downstream S2. See S2_2323-18_496um_Bias_Vs_Leakage_Current_050418.png

RAL 1 CH1 looked clearer than yesterday, 0,6V pulser setting produces 3V signal. However there was a strange reflection on the end tail of the pulser peak. I mounted both preamp lids but still saw the reflection. This effect dissapeared after disconnecting the diode preamp test input from the daisy chain with the S2 preamp boxes. I replaced this with a 50 ohm terminator.

We adjusted the downstream S2 RAL thresholds (they were 15mV to begin with except RAL I (100mV) which was adjusted yesterday)

Now the thresholds are:

We tried starting the DAQ using an OR trigger from the downstream S2, however we were presented with an error: Too Many Bad Events

We tried disconnecting all of the RAL ECL outputs except RAL I's, we still recieved the error.

We tried increasing the pulser amplitude setting from 0.2 -> 0.6V, still recieved the error.

We tried restarting the FAIR DAQ, after restarting we got good events. We can see a pulser peak and two alpha peaks.

We reconnected the ECL outputs for RAL II -> RAL VIII to the DAQ OR trigger

Note: ADC 2 (module 3) still shows strange "TDC-Like" behaviour, so we avoid this module.

The first 8 channels of RAL I still show alot of noise, we increased RAL I threshold from 90 to 100 mV

Triggering DAQ only on downstream S2, we see a dead time ~ 9% and trigger rate ~3700Hz

I tried removing the downstream preamp box lid and checked both the preamp -> feedthrough and also the preamp -> IDC convertor box connections on the preamp PCB. I resealed the preamp box lid.

Check on RAL I CH1 (downstream S2) noise: for pulser setting 0.5V amplified peak has height 2.8V noise 100mV

Check on RAL X CH 1 (central S2) noise, for same pulser setting amplified peak has height 2.8V noise 100mV, signal to noise ratio ~ 3.57% for both channels

We then connected the central detector ECL signals to the 3rd and 4th MALU 4532 Logic modules in the CAMAC crate. RAL X -> "R" sent to ADC 4, RAL "S" and "Q" sent to first 16 channels of ADC 5. Channel 31 of ADC 5 is diode. Currently the diode CFD threshold = 200mV. RAL X -> "Q" thresholds were all kept at 15mV.

We set the DAQ trigger to an OR of all 129 channels (64 from each S2 and 1 from diode)

Started DAQ, dead time 9%, trigger rate 3500 Hz, event mult = 52.5.

We decided to run an alpha spectrum.

Pulser Settings:

• Fall Time = 100us
• Rate = 10Hz
• Delay = 250ns
• Ampl = 0.5V
• Pol = POS
• Pulse Top = Tail
• Atten = 1X
• Clamp = OFF

14:55 started DAQ for 15 min alpha spectrum, save name: /Remote_Objs/RData_1/180405140038

Dead time = 71%, trigger rate ~ 1600Hz, event mult = 57.6

On 04/04/18:

We mounted S2 2323-18 (496um) in the downstream position with 12um mylar

We mount the central and downstream iris arms, we set the central arm position to 14.0mm and the downstream arm position toe 1.5mm - opening both irises.

We started Ecodry 1 and 2, we checked T1600 Backing valves was closed. At 10:11 cracked open the gate valve. After several minutes of pumping Ecodry 1 cutoff, suggesting a big leak.

The downstream chamber lid was sitting at a slight angle, we vented the chamber and reset the downstream aperture to 82.5mm. We removed the downstream aperture. Lifting off the downstream lid we found the O-ring between the lid and collar was not correctly in its groove, this was corrected.

We closed the downstream lid and remounted the downstream aperture. We set the aperture back to 1.5mm (iris open). We closed the turbo vent valves ready for a second venting attempt.

There was a problem with the Labview DAQ, Guiseppe and Raffaele fixed this.

Ecodry 1 and 2 were switched back on, at 11:20 the gate valve was opened. At 11:28 the gate valve was fully opened and pressures read < 1mBar on all 6 gauges. T1600 Backing valves was opened allowing Ecodry 2 to pump on chamber. At 11:31 all 7 turbos were switched on.

During pumping we began mounting the preamp boxes onto the chamber. We discovered the preamp box to be mounted on the central lid needed its holes enlarging to accomodate the bolts for mounting the preamp box to the spacer box.

We mounted the downstream preamp box first, currently holding preamp 2 with the now copper taped preamp - feedthrough signal cable. We then mounted the central preamp box, holding preamp 1 with a copper taped preamp - feedthrough signal cable.

We daisy chained the preamp -15V and +15V cables for the two S2 preamp boxes and the diode preamp, we also daisy chained the +ve test input for the two S2 preamp boxes.

Originally, the central S2 HV was connected to the Silena module CH1, the downstream S2 HV was connected to Silena CH 2, and the diode HV was connected to Silena module CH3.

Powering the diode to -70V, leak I = 0.00uA.

However when powering the S2s to -130V, no leakage current was observed. It turned out the silena CH2 did not work, moving the downstream S2 HV to silena CH4 and powering to -130V reads 1.69uA leakage current.

For the central S2 the problem was found on the respective preamp box. It turned out the SMA connection of the BNC->SMA feedthrough was loose, tightening this and powering the central S2 to -130V reads a leakage current of 2.47uA.

The target ladder was set to position VII - alpha source facing downstream.

Checking RAL signals for central detector, RAL X, XII, XIII, R, S, Q all looked good, RAL U CH 6 was dead, RAL W channel 0 and 1 were dead.

We discovered RAL I (dowsntream S2) showed poor noise, for a 0.2V pulser setting, the amplified signal on RAL I CH 2 was ~5V with noise ~400mV. See 20180404_Pulser_PreampLid_ON.jpg

I emailed Tom Davinson for ideas, he suggested checking what happens when the preamp is disconnected from the vacuum feedthrough.

When the preamp was disconnected from the vacuum feedthrough the amplified signal on RAL I CH 2 was ~1.5V with noise ~40mV. 20180404_Pulser_DisconnectedFromFeedthrough.jpg

We collected vias vs leakage current curves for the two detectors. See attached S2_2323-18_496um_Bias_Vs_Leakage_Current.png for the downstream S2 and S2_2623-26_505um_Bias_Vs_Leakage_Current.png for the upstream S2.

I suspected the new cable between the downstream S2 and vacuum feedthrough is damaged - perhaps it has a short.

I also checked the central S2, again for a pulser setting of 0.2V RAL X CH 1 showed a 1.2V signal with ~50mV noise, which seemed a better case than for the downstream S2.

The time was 20:20, we decided to stop for the day. The turbos, Ecodry 1 and 2, both S2s, the diode, and the preamp power were switched off ready for dismounting the downstream S2 for a cable change the next day.

This morning I unpacked the chamber parts.

I mounted the downstream and central lids with the iris arm hooks to double check we could still successfully mount them, see previous eLog entry (#25) for photos from this procedure performed in Edinburgh.

When attempting to move the aperture arm, I noticed the hook was catching on the Al tube used to support the aperture onto the side of the chamber collar. I cut the hooks used for both the downstream and central apertures, they still hooked onto the iris arm.

The actuator positions were found as follows:

Downstream:

Mounting (iris "closed" to ~18mm diameter) aperture setting = 82.5mm

During measurement (iris open) aperture setting = 1.0mm

Central:

Mounting (iris "closed" to ~18mm diameter) aperture setting = 87.0mm (Old = 85.5mm)

During measurement (iris open) aperture setting = 14.0mm

Note: these were measured by moving the actuator arm away from the chamber collar (105 -> 0 on actuator scale). This is to avoid backlash in the position, particularly because the iris arm hole allows moderate (~4mm) movement of the aperture arm hook.

I then cleaned the upstream, central, and downstream lids, the chamber collars o-rings and top and bottom surfaces, and the metal part of the diode mount all with alcohol.

Me and Raffaele mounted the chamber collar onto the chamber target section (already mounted on beamline from February 2018 shifts)

We then attempted to mount the downstream lid, with S2 detector mask, onto the collar, however we had difficulty connected the iris arm to the actuator hook. This was also the case for the central lid.

We decided to implement a new approach, this requires 2 people to ensure the aperture can be adequately supported during mounting:

1. Leaving the aperture off of the chamber collar, mount the chamber lid (downstream/central) with iris arm mounted

2. Using tweezers or another small tool, gently pull the iris arm out through the chamber collar side hole

3. Using the iris arms hole, hook the aperture arm onto the iris arm

4. Carefully insert the aperture into the chamber collar side hole, whilst simultaneously shortening the aperture arm to ensure the arm will fit

5. Bolt the aperture onto the side of the chamber collar

We performed this operation for both the downstream and central lids, we were successful in both cases on our first try. The irises were visually seen to open and close by looking through the beamline from the position of FC-E0.

When mounted the iris "closed" (18mm diameter) positions were:

Downstream = 82.5mm,

Central = 85.5mm (suggesting my 87.0mm quoted above is due to the iris arm hole size)

On the central lid I mounted the diode at 39 degrees and 22.0mm from the upstream side of the lid. This was very efficient due to the new mounting block. See pictures IMG_2823 and IMG_2839

I also mounted the S2 2623-26 in the central position with 12um mylar. See attached IMG_2841

In the meantime Raffaele mounted the target ladder with the following targets:

I need to check the CH2 target number at position 3. Target VII was removed from position 3 because it looked like it was peeling off -> needs additional epoxy

At 18:45 we left the lab.

Tomorrow morning we intend to mount the downstream S2 detector with 12um mylar and both aperture hooks. We then plan to pump down the chamber, setup the electronics, and perform an alpha source calibration.

If all goes well we will perform a beam measurement of 7Li at 5.0 MeV

Between 7th to 21st March modifications were made to the top of the CIRCE target chamber.

These modifications address the three key issues highlighted during the February shifts

1. The central S2 detector did not fit, because its connector pins came into contact with the chamber lid

Additional machining was performed on the central chamber lid, allowing the pins to fit

2. Mounting the iris hooks was non-trivial, resulting in the inability to open and close the irises whilst the lids were mounted on the chamber

Peter designed a guide rod allowing the hook to be connected to the iris arm before mounting the lid onto the chamber. Now the only difficult part is ensuring the actuator arms hook connects to this guide rod.

I checked the position settings needed for both actuators when mounting or removing the chamber lids, these are:

Central actuator setting = 85.5mm

Downstream actuator setting = 82.5mm

The actuator positions for a fully opened iris still need to be checked in CIRCE.

When mounting the lids the guide rods will be arranged such that the irises are in the mostly-closed position (~16mm diameter). This reduces chance of damage made to the S2's during installation and removal, and also means the iris is already setup ready for beam tuning.

See attached pictures for the downstream and central lids.

A sample S2 in Edinburgh was used to check the connectors fit with the lid and other parts. When mounting the lids onto the chamber collar it was decided to leave the S2s off the iris mount. This was to avoid the risk of damaging the S2 from slippage of the parts - note in CIRCE the collar will be on top of the target section with threaded rods and so the conditions are more stable than on tabletop. During lid mounting, the metal mask was used in place of the S2 to simulate its size.

Marks "CE" and "DW" were made respectively on the central and downstream lids and guide rods.

3. The pin diode angle was not reproducible

A mounting block has been machined in Edinburgh, it has an angled slant of 39.0 +/- 0.5 degrees for setting the angle of the plastic block used to support the diode. We noticed in the CAD drawing that mounting the diode at the closest distance to the target would mean the target frame is likely to cause scatter from the backscattered beam, therefore we chose to mount the diode in its central position. The angled block has a width 22.0 +/- 0.1mm for setting the distance between the back of the diode mount and the upstream side of the central chamber lid.

An excel spreadsheet was used to calculate the diode angle, see attached "DIODE_ANGLE_CALCULATION.xlsx"

The chamber parts were shipped back to CIRCE and arrived on 26/03/18, the mounting block and PB-5 Pulse Generator were also sent in the same shipment.

Today we began examining and modifying parts of the chamber shipped from CIRCE to Edinburgh.

The parts shipped were:

• Chamber Collar
• Central Lid
• Downstream Lid
• Two Metal Detector Masks
• Two Iris Mounts
• One Iris
• Two Actuators
• Pin Diode Mount

This morning we began piecing parts of the chamber one by one, starting with putting the lids on the collar and checking how easily the iris arms fit. We found whilst fitting together the chamber that the actuator used to control the downstream iris will need to be moved further away from the chamber than the current Al tubes allow. This is because currently the aperture arm hits the metal iris mount. By moving the actuator further away there will still be space for a thin wire to hook onto the iris arm.

Originally the S2 detector was intended to be mounted with the front strips facing downstream. We found in CIRCE during the recent February shifts that this was not possible, because the connectors on the detector PCB hit the lid.

Today Peter machined space for the downstream detector connector, so now the detector may be mounted as originally intended. We checked the vacuum feedthrough still fits too.

However, the ribbon cable between detector and feedthrough will still come between the actuator arm and the iris arm, so adjustment of the iris from outside the chamber is still not possible. We are still working on this.

On 23/02/2018:

At the end of the February 2018 shifts the detectors bias settings were:

S2 bias = -130.3V, leak I = 2.42uA

Pin diode bias = -70.1V, leak I = 0.00uA.

Both detectors were switched off, the preamp power was also switched off.

At 18:22 the chamber pressures read:

TPU1 = 2.3e-6 mBar

TPU2 = 6.9e-7 mBar

TPD1 = 1.6e-6 mBar

TPD2 = 1.7e-6 mBar

CHUP = 5.7e-6 mBar

CHDW = 1.5e-5 mBar

We closed the manual gate valve and T1600 Backing Valves. We switched off the turbos and roughing pumps Ecodry 1 and 2.

The nim bin for the quad bias and other nim modules was switched off. The Lecroy 1434A CAMAC Crate was switched off. The RAL shaping amp crate was switched off.

We put away the S2 and pin diode detectors.

The alpha source was removed from the target ladder.

The target ladder was remounted in the following configuration:

We performed a general tidy-up around the chamber and workspaces we used during the past 9 days.

I took the PB-5 Pulse Generator and three 64 Way - 2X32 Way ribbon cables (for minor modification) back to Edinburgh.

I also took the mylar we discovered in the beamline on Tuesday 20th as a keepsake/ reminder anything can happen

At ~20:00 we declared victory for the week.

On 23/02/2018:

After the alpha source calibration of the S2 (See eLog entry #21) we decided to perform a pulser walkthrough for the pin diode on ADC 6 CH 31.

The pulser was only connected to the pin diode preamp to ensure it wasnt being split.

Note: Since the pulser is still being 50 ohm terminated the amplitude setting is divided by 2 regardless of any signal splitting. Example: Setting a pulse height of 1.0V on the PB-5 corresponds to an output pulse height of 0.5V.

The pulser settings for this walkthrough were:

Fall Time = 100us

Rate = 10.00Hz

Delay = 250ns

Ampl = varied 1.0V -> 0.25V

Pol = POS

Pulse Top = Tail

Atten = 1X

PB-5 Pulse = ON

CLAMP = OFF

For this test we also needed to change the Delay Amp 1457 delay setting from 1us to 3us to ensure pulses were occuring after the DAQ OR trigger

I collected a DAQ run for the following pulse amplitude settings:

0.1V, 0.15V, 0.2V, 0.25V, and 0.3V

We also attempted 0.05V and 0.07V but were unable to see a clearly defined peak in the spectrum - likely caused by the high level of noise from the CFD we see at the low ADC channels. This should be better optimised at the start of the next shifts.

The save name for this pulser walkthrough is: Remote_Objs/RData_1/180223180747

See attached "180323_PulserWalk_PinDiode_ADC6CH31.png" for the pulser walkthrough spectrum.

On 23/02/2018:

We moved the target ladder to position 7, 5.019mm, with the alpha source facing downsteam.

At 17:17 we started the DAQ for a 15 minute alpha spectrum on the downstream S2. Save name: /Remote_Objs/RData_1/180223172135

The trigger rate ~ 160 Hz, Event Mult. = 5.8, Dead time = 0%

Note: For both this alpha spectrum and the beam measurement at 3.45 MeV 7Li (See entry #20) the pulser test input was also plugged into the diode preamp, hence the pulser peak appears at a lower channel in the S2 spectra. It still does not overlap the alpha peaks.

See attached "180223_Alpha_S2FrontStrip_ADC2CH20.png" for sample alpha spectrum of front S2 strip

See attached "180223_Alpha_S2BackStrip_ADC4CH24.png" for sample alpha spectrum of back S2 strip

In the S2 front strips we observed some additional peaks at lower channels ,~500, to the alpha peaks, but were unsure what they were. We decided to run a background to confirm whether this was caused by the source.

We moved the target ladder to position 1, 95.010mm, to position the alpha source as far from the central beam axis as possible. We then collected a background run for 5 minutes 16 seconds. Save name: /Remote_Objs/RData_1/180223174450.

We did not observe these low channel peaks in the background run, suggesting they are the result of the alpha source - perhaps a geometry effect.

On 23/02/2018 at 13:49 we started the DAQ in list mode.

After starting the DAQ we sent the 3.45MeV 7Li beam onto the CH2 930ug/cm2 target III.

The trigger rate ~ 2kHz, event multiplicity = 6.1, dead time ~ 9%.

The DAQ save file is: /Remote_Objs/RData_1/180223135345

Checking the ADC rate histograms:

• ADC 2 Channels 0->7 Rate ~ 1e3 (channels 0 and 5 still disabled)
• ADC 2 Channel 8 dead
• ADC 2 Channels 9->31 Rate ~ 1e4 - 1e5
• ADC 4 Channels 0->15 Rate ~ 1e3
• ADC 4 Channels 16 -> 29 and 31 Rate ~ 1e4 - 1e5
• ADC 4 Channel 30 dead
• ADC 6 Channel 31 Rate ~ 8e5

Picking an S2 backstrip at random we found a proton detection rate ~ 100Hz, no high rate beam scatters were seen, as expected from the thick target. We decided to run for several hours.

We performed occasional checks during the run:

Where the area regions used (in channels) for each ADC Channel are:

ADC 2 Ch 20: 0->552

ADC 6 Ch 31: 1302->1475

ADC 4 Ch 24: 20 ->549

The ratios use the number of counts since the previous check. The ratios are decreasing as expected, because this indicates that fewer protons are being detected during the irradiation time.

At 17:08 the DAQ was stopped at runtime 03:19:02

The DAQ monitor dead time ~ 5%. Event multiplicity ~ 6.0, # Good events = 23917715.

We checked the beam current before the chamber, FC-E0 ~ 190pA.

See attached "180223_S2FrontStrip_ADC2CH20.png" for sample front S2 strip spectrum

See attached "180223_S2BackStrip_ADC4CH24.png" for sample back S2 strip spectrum

See attached "180223_PinDiode_ADC6CH31.png" for sample pin diode spectrum

On the morning of 23/02/18 we aimed to complete beam tuning of 7Li at 3.45MeV.

At 8:43 CHUP = 7.2e-6mBar, CHDW = 1.9e-5mBar.

The S2 bias was ramped to -130.3V, leak I = 1.67uA. The diode bias was ramped to -70.1V, leak I = 0.01uA. The preamp power was also switched back on.

With no beam the DAQ monitor read a trigger rate ~ 50Hz and event multiplicity = 5.3.

We started beam tuning. A mistake was made where the accelerator side of the wrong valve was opened at the bending magnet, causing the beamline to be vented from 10^-7mBar to 10^-3mBar. Fortunately the line valve was closed, so the pressure of the chamber holding the detectors was unaffected.

We struggled with beam tuning for a few minutes, until we discovered the venting of the beamline tripped an interlock, causing turbo entrance 1 and 2 to be switched off. Restarting these turbos both improved the accelerator beamline vacuum and the beam tuning.

After beam tuning with the 3mm blank frame, we achieved beam currents:

FC-E0 (pre-chamber) = 250 pA

FC-E1 (post chamber and GSSI magnet) = 185pA

Transmission ~ 74%.

We felt satisfied and decided to remove the 12um mylar from the S2 ready to perform the measurement.

At 10:39 both detectors and the preamp power were switched off. The turbos were switched off. The manual gate valve and T1600 gate valves were closed. Ecodry pumps 1 and 2 were switched off. (We should write a procedure for pumping down and venting the chamber)

During venting we removed the S2 preamp box from the top of the chamber.

At 11:05 the CSSM gate valve interlock was tripped. In future we should make sure the CSSM magnet is OFF when not in use. David checked the pressures in and around the chamber, he concluded everything was fine.

After venting the chamber I removed the 12um mylar from the front of the S2.

I also removed the target ladder and rotated the alpha source 180 degrees to face downstream - this is so we can obtain a second alpha calibration of the S2 at the end of the beamtime.

Whilst handling the target ladder I noticed target VII is loose at one side, either from beam or my epoxy skills. I decided to leave all the targets mounted and we run beam on target 2, located at target ladder position 4, 50.015mm.

The target ladder configuration is now:

At 12:18 the chamber was sealed up and we began roughing it down. At 12:29 we started the turbos and went to lunch.

At 13:02 after lunch: CHUP = 9.7e-6mBar and CHDW = 2.5e-5mBar.

We remounted the S2 preamp box back onto the downstream chamber lid, the preamp box lid was also remounted. The following pin diode preamp box cables were replugged in: input, -15V, +15V, +ve test, and HV.

At 13:25 the pressures read: CHUP = 9.6e-6mBar and CHDW = 2.5e-5mBar.

The S2 was biased to -130.3V, leak I = 1.56uA. The diode was biased to -70.1V, leak I = 0.01uA. Preamp power was applied -> correct currents drawn.

The target ladder was set to position 4, 50.015mm, target: CH2 930 ug/cm2 target III.

With no beam the DAQ trigger rate ~ 50Hz, the beam current at FC-E0 = 240pA.

We were confident to begun a beam measurement.

Checking SRIM 3.5 MeV 7Li is stopped in 9.06um mylar or 10.09 um CH2.

After the long run at 3.0MeV on 22/02/2018 we decided to put the 12um mylar back in front of the S2 and start tuning the beam for 3.45MeV 7Li. We also decided to tune the beam to a higher current of ~ 100pA to try and improve the detection rates.

At 20:54 The turbos were switched off. The manual gate valve for Ecodry 2, automatic gate valve for Ecodry 1, and line valves were closed.

Whilst the turbos spun down we removed the S2 preamp box from the top of the chamber.

At 21:31 the vent valve at FC-O was opened. At 21:49 we noticed the chamber was vented.

The S2 was removed from the chamber and 12um mylar mounted in front of it. The S2 was remounted in the downstream section of the chamber.

At 22:03 the manual gate valve was cracked open -> we began roughing the chamber with Ecodry 2. At 22:18 the manual gate valve was fully opened and we then opened the T1600 Backing valve allowing Ecodry 1 to pump the chamber. We then started the turbos.

During pump down the S2 preamp box was remounted on top of the downstream chamber lid. The lid to the preamp box was also mounted. The following pin diode preamp cables were reconnected: -15V, +15V, +ve test, input from lemo feedthrough, and HV.

By 22:34 the pressures in the chamber were CHUP = 1.3e-5mBar, and CHDW = 3.2e-5mBar. The S2 was biased to -130.3V, leak I = 1.54uA. The diode was biased to -70.1V, leak I = 0.00uA. The preamp power was switched on, correct currents were being drawn.

The target ladder was set to position 2, 80.024mm, no target or frame.

After tuning with no target, the GSSI slits were fully open at:

Up = 0mm

Down = 5.5mm

Right = 1.5mm

Left = 5.5mm

We found the following currents:

FC-4 = 740pA (upstream from bending magnet)

FC-0 = 430 pA (upstream from chamber)

FC-E1 = 70pA (downstream from chamber and GSSI magnet)

The target ladder was moved to position I, 95.010mm, blank 3mm frame.

After further beam tuning we obtain currents:

FC-E0 = 330pA

FCE1 ~ 200pA

Transmission: ~63%

At 23:33 CHUP = 6.5e-6mBar, and CHDW = 1.7e-5mBar. S2 bias = -130.3V and leak I = 1.66uA. Diode bias = -70.1V and leak I = 0.00uA.

We decided to call it a day. Both the S2 and diode was switched off for the night. The accelerator beam voltage ~ 1.4730MV.

Raffaele let a note for Liz to improve the transmission to 70% the next morning (23rd).

See next eLog entry #19 to continue the beam tuning adventure.

Yesterday (21st) night we saw this low channel, high rate (1500Hz) noise on the diode spectrum - see eLog entry #15.

This morning the S2 bias was ramped to -130.3V, leak I = 1.43uA. Diode bias ramped to -70.0V, leak I = 0.01uA.

Starting the DAQ with no beam, the trigger rate is ~250 Hz, with most triggers coming from the diode. Inspecting with the oscilloscope we find a very high noise of ~300mV. The amplifier course gain = 1K.

Lowering the course gain to 200 we decided to try sending beam on target VII and check the diode output on the oscilloscope. I was able to see some signals at ~3V, with very low rate ~0.1Hz

I checked the rutherford scattering rate using the Nuclear_Reaction-master.xlsx excel file, sheet "Rutherford Scattering" columns BH and BP. See attached.

With the current collimator radius = 0.5mm, at our scattering angle 152 degrees, we find an expected rate 2.72e-3 particles per second.

We decided to remove the diode collimator, for the 10X10mm diode this would give an expected rate 0.272 particles per second. This is still not ideal, and before the next shifts we should optimise the position of the diode to improve the rates. This is for a beam current ~40pA, so we would benefit from higher beam current too. A rate of 5 - 10 particles per second would be nice. For now we stuck with the current situation.

At 10:52 the S2 and diode biases were switched off. The preamp power was also switched off. The turbos were also switched off. By 11:48 I saw the turbos had stopped spinning and started venting the chamber.

Once the chamber was vented we managed to remove the central lid without needing to remove the S2 preamp box on the downstream lid.

The 1mm diameter collimator was removed from the diode, this completely destroyed the 0.9um mylar in the process. Next shifts we will use a metal plate to glue the mylar in place, avoiding this issue. For now we left no mylar in front of the diode, because this will not be useful until running 7Be beam.

We also decided to remount the alpha source, allowing us to check the diode is functioning as expected. The target ladder configuration is as follows:

After removing the diode collimator the central lid was remounted and at 12:50 the roughing pumps started. At 13:12 the turbos were started.

By 13:53 the pressures read CHUP = 1.2e-5mBar and CHDW = 3.3e-5mBar.

We switched on the preamp power. The S2 bias was ramped to V = -130.3V, leak I = 1.25uA. The diode bias was ramped to -70.0V, leak I = 0.01uA.

The target ladder was moved to position 7 (5.019mm), centering the alpha source in the beam axis and pointing upstream.

We were able to see the two highest intensity alpha peaks in the pin diode spectrum (ADC6 CH31) - so the diode is certainly working

At 14:06 we started an alpha calibration run for the pin diode.We collected data for a preset time 900 seconds. The trigger rate ~80Hz, Event Mult. = 3.0, dead time = 0%.

The save name is: /Remote_Objs/RData_1/180222141134

See attachment PinDiode_AlphaSpectra.jpg for a sample spectrum

The Ortec 871 Amplifier Settings were:

Fine gain = Max

Course gain = 50

Shaping time = 0.5us

BLR Auto On

The Delay Amp 1457 settings were:

Delay: 1us

Range: 10V

Polarity: Pos

At 14:21 the DAQ stopped, # good events = 61406.

Now we were ready to proceed with a beam measurement.

The target ladder was moved to position 3, 65.000mm, target: CH2 930ug/cm2 VII

We still see some alphas from the source, these are 5.1->5.5MeV, and from the kinematics we expect the beam scatters to be ~2.9MeV so there should be no overlap in energy.

I disconnected the pulser from the pin diode (it was set to too high an amplitude to appear on the alpha spectrum) and switched it ON for the S2 front strips. The pulser rate was changed from 10Hz to 2Hz. (Set to 10Hz when diagnosing pin diode)

With no beam trigger rate ~85Hz, event mult. ~ 8.0

We checked the beam at FC-E0, just upstream from chamber, = 45pA

We bombarded CH2 VII with 3.0MeV 7Li beam, trigger rate ~700Hz.

The pin diode rate for backscattered beam was very low, but we do see some counts at channel ~1300, which is expected.

We decided to run for 1 hour and see the rates.

15:00 DAQ started for 3.0MeV 7Li on CH2 930 ug/cm2 target VII

Save file: Remote_Objs/RData_1/180222150540

Trigger rate ~ 550Hz, Event Mult. ~ 6.2, dead time ~4%

Note: from previous tuning and running yesterday (21st) I estimate beam has already bombarded target VII for ~3 hours before starting this run.

At run time = 01:01:09 we have the following areas:

ADC 6 CH31 (pin diode) area between channels 1159->1268 = 285

ADC 4 CH24 (S2 back strip) total area = 7353

ADC 2 CH 3 (front S2 strip) total area = 21647 (2Hz pulser connected)

Ratio of back strip to diode = 76.0

We decided to collect data until 20:00 giving us ~5 hours of data at 3.0MeV.

At DAQ runtime = 03:03:09 we have the following areas:

ADC 6 CH31 (pin diode) area between channels 1159->1268 = 911

ADC 4 CH24 (S2 back strip) total area = 66704

ADC 2 CH 3 (front S2 strip) total area = 22335 (2Hz pulser connected)

ADC 2 CH 7 (front S2 strip) total area = 22734 (2Hz pulser connected) - more statistics than ADC2 channel 3, continued monitoring this channel instead of channel 3

Ratio of back strip to diode = 73.2

Ratio of last ~2 hours runtime = 71.0, so target is degrading

At 19:25 we decided to go to dinner and leave the setup to collect data.

At this time CHUP = 5.4e-6mBar, CHDW = 1.4e-5mBar. S2 bias = -130.3V, leak I = 1.71uA. Diode bias = -70.1V, leak I = 0.00uA.

At 20:50 we returned from dinner. The DAQ was manually stopped.

DAQ monitor:

Run time = 05:49:09

Event mult. = 6.2

Dead time =7%

# good events = 34296773

At the end of data collection the areas are:

ADC 6 CH31 (pin diode) area between channels 1159->1268 = 1847

ADC 4 CH24 (S2 back strip) total area = 124876

ADC 2 CH 7 (front S2 strip) total area = 43334 (2Hz pulser connected)

Ratio of back strip to diode = 67.6

Ratio of last ~ 3hours = 62.1 - so target is still degrading

The S2 bias = -130.3V, leak I = 1.75uA. S2 Bias ramped OFF

The diode bias = -70.1V, leak I = 0.00uA. Diode bias ramped OFF

Preamp power OFF

At 20:53 the pressures read:

TPU1 = 2.5e-6mBar

TPU2 = 6.4e-7mBar

TPD1 = 1.6e-6mBar

TPD2 = 1.6e-6mBar

CHUP = 5.2e-6mBar

CHDW = 1.3e-5mBar

See attached 180222_diode.jpg for the final diode spectrum.

See attached 180222_ADC4CH24.jpg for the final S2 back strip spectrum

See attached 180222_ADC2CH7.jpg for the final S2 front strip spectrum

DAQ Settings for ADC6 settings attached. ADC 6 has been used for the pin diode during the week starting 19/02/2018

On 21/02/2018 after beam tuning and pumping down at 18:07 the pressures read Up = 1.2e-5mBar, Down = 3.2e-5mBar. We were happy to power the detectors and try to observe spectra from beam in both the S2 and pin diode.

Whilst waiting for the turbos to spin up the Pin diode was daisy chained with the +ve pulser, +15V, and -15V preamp power cables used with EDI Preamp 2 for the S2.

Channel 3 of the Silena Quad Power Supply was set to -70V ready for the diode.

The S2 bias was ramped to -130.3V, leak current = 1.19uA. The Pin diode bias was ramped to -70V, leak current = 0.01uA.

The preamp power was switched on, +15V read current 0.8A, -15V read current 0.4A, as expected.

The pin diode output was split between an Ortec 571 Amplifier and channel 2 of a Quad TFA.

The unipolar output of the Ortec 571 Amplifier was sent to a Delay Amp 1457. The Delay Amp output was sent to ADC 6 Channel 31.

The Quad TFA output was sent to channel 4 of a Quad CFD. The CFD output was sent to the Lecroy 622 module and setup as an OR with the S2 strips. This OR is sent to the DAQ trigger.

We mounted the preamp box cover. The grounding cable for the ribbon signal cables was attached to the box. We confirmed the grounding of these ribbon cables with a voltmeter.

Now with no beam the DAQ trigger rate ~ 60Hz. This suggests the ~6kHz rate seen before is noise from the previously exposed preamp, note the downstream turbo is very close (a couple centimeters) to this preamp.

To double check the tuning was still ok we sent the 7Li beam to FC-0 = 48pA.

We decided to close the GSI slits located before the quadrupole and slowly open these to their values in eLog entry #14. We closing the left and right slits had no effect on reducing beam current, so we kept these positioned at 5.5mm and 1.5mm respectively. The up slit was already 0.0mm.

Slowly opening the down slit we saw the following:

We saw on the backscattered diode counts at channels 50 -> 400, even when increasing the Ortec 571 Amplifier gain to 1K and the fine gain to maximum.

We checked the faraday cup upstream from the bending magnet, FC-4 = 100pA.

We also checked the faraday cup just upstream from the chamber, FC-0 = 53 pA.

The Ortec 571 Amplifier settings (for pin diode) were:

Fine gain = Max

Course gain = 1K

Shaping time = 0.5us

Input = Neg

BLR AUTO ON

Uni Output taken with Out setting

The Ortec 935 Quad CFD CH4 threshold was = 175mV

At 20:50 we sent 3.0 MeV of 7Li beam onto CH2 930ug/cm2 Target VII. We started the DAQ whilst writing to disk.

The DAQ dead time ~ 3%, Trigger rate ~ 1500 Hz, Event Mult. = 6.2.

The save path and name: /Remote_Objs/RData_1/180221205456

It became apparent within the first 1/2 hour that the trigger rate (1500 Hz) is almost entirely from the pin diode.

At 22:10 we stopped the DAQ data collection, run time = 01:19:46, dead time = 4%, # of Good Events = 7180956.

We checked the current on FC-0 = 53 pA.

The beam voltage ~1.2730 MV.

Checking the detectors: The pin diode voltage = -70V, leak I = 0.00uA. The S2 bias = -130.3V, leak I = 1.46uA. Both detectors were switched off for the night.

At 22:18 the pressures in the chamber are:

TPU1 = 3.4e-6mBar

TPU2 = 7.5e-7mBar

TPD1 = 1.5e-6mBar

TPD2 = 1.8e-6mBar

CHUP = 6.1e-6mBar (also referred to as Up)

CHDW = 1.6e-5mBar (also referred to as Down)

See attached "180221_PinDiode.png" for the pin diode spectrum after the run. In the morning of 22/02/2018 we realised this was just amplified noise.

See attached "180221_S2BackStrip_ADC4CH24.png" for a sample spectrum of one of the S2 back strips

See attached "180221_S2BackStrip_ADC2CH7.png" for a sample spectrum of one of the S2 front strips

On 21/02/2018 we reattempted the beam tuning. We expected this to be easier now the rogue mylar is removed from the beamline.

At 8:30 we started the roughing pumps. At 8:37 the turbos were switched on. By 8:55 the preassures read: Up = 1.6e-5, and Down = 4.3e-5 mBar.

The preamp box was mounted on top of the chamber ready, the box lid was still left off.

The S2 was biased to -130.3V, leak current = 1.03 uA.

On FAIR DAQ with no beam: Trigger Rate ~ 8000/s, Event Mult = 5.0

The 10mm blank frame was in the beam axis. We began beam tuning. By 11:30 we had beam on the downstream faraday cup FC-E1 = 40pA, so now we can pass beam through the chamber - good!

We moved the target ladder to 95.010mm, swapping from the blank 10mm frame to the blank 3mm frame to assist in beam tuning. Now FC-E1 ~ 8pA.

We decided to move back to the 10mm frame to optimise tuning. The target ladder was moved back to position 80.024mm for this purpose.

We moved the slits located upstream from the bending magnet (close to FC-4) to 1.5X1.5mm.

We moved the GSI slits located before the quadrupole to optimise current on FC-0, the upstream faraday cup. We find the following slit positions:

Up = 0mm, Right = 1.5mm, Down = 5.5mm, Left = 5.5mm.

We also performed further tuning by adjusting the quadrupoles located at the immediate end of the tandem accelerator - note the beam tuning is very sensitive here.

After beam tuning we had the following currents:

For 10mm blank frame in beam axis: FC0 = 42pA, FCE1 = 30pA, transmission ~ 71%

For 3mm blank frame in beam axis: FC0 = 41pA, FCE1 = 13pA, transmission ~ 32%

We decided this was acceptable for testing

At 13:30 we switched off the S2 and vented the chamber.

After venting we did the following:

• Removed 12um mylar from the front of the S2
• Visually inspected the ribbon cable connections on the S2 connector and the vacuum feedthrough connector. I saw no loose connection and left the cable alone.
• Set the Si diode angle to 62 degrees relative to the beam axis (28 degrees relative to the normal of the beam axis) - in future we need a fixed angle mount to ensure this angle is reproducible
• Mounted targets on the ladder at the following positions:

The target ladder was set to position 3, looking from above I confirmed it was in the center of the beam axis.

The alpha source was removed as someone pointed out the ladder may be moved in such a way that beam hits the source. However later on (morning of 22/02/2018) I was informed this is being over cautious and we can leave the source at the far position 7 of the ladder during beam.

The ladder, downstream, and upstream lids were remounted on the chamber. The S2 (no mylar) was still on the downstream lid. The diode was still on the central lid.

The roughing pumps were switched on. However the following mistake was made: when both Ecodry 1 and Ecodry 2 were switched on, the automatic gate valve for Ecodry 1 was still open. This meant the chamber was evacuated at a fast rate, likely > 10mBar/s. When I noticed this after a few seconds of pumping the pressures read 10^-1mBar at the chamber upstream and downstream positions.

Speaking to David I learned Ecodry 1 may be switched on ready as long as the gate valve "T1600 Backing" is closed

Learning point: Ensure the automatic gate valve "T1600 Backing" is closed before pumping. This way we can control the roughing speed using the manual gate valve on Ecodry 2.

I wanted to inspect if anything was damaged in the chamber by this fast pump speed. The pumps were stopped and the chamber vented.

Upon visual inspection the S2 and 0.9um mylar in front of the diode were undamaged.

Target CH2 I on the ladder was loose at one side, the target ladder was removed and CH2 I at position 3 was replaced with CH2 VII.

Now the target ladder is in the following configuration: See attached IMG_2738.jpg

At 16:45 the roughing pumps were switched on, this time with the "T1600 Backing" gate valve closed. The manual valve was cracked open.

By 17:01 the pressures read Up = 4.2e-1 mBar, Down = 4.1e-1 mBar.

At 17:08 the turbos were switched on.

At 18:07 the pressures read Up = 1.2e-5mBar, Down = 3.2e-5mBar.

We are ready to connect the preamp box for the S2, and also connect the preamp for the pin diode.

The PB-5 Pulse Generator settings are as follows:

Fall Time = 100us

Rate = 2.00Hz

Delay = 250ns

Ampl = 0.50000V

Pol = POS

Pulse Top = Tail

Atten = 1X

PB-5 Pulse = ON

CLAMP = OFF

During the second beam tuning on 20/02/2018 we performed two pulser walkthroughs to determine the ADC offset.

For the walkthrough the rate was increased to 10Hz.

The first pulser walkthough was saved as: Remote_Objs/RData_1/180220170900

The pulser amplitudes used were: 0.1, 0.2, 0.3, 0.4, and 0.5 V

After this walkthrough I remembered channels 24 -> 31 of ADC 2 were unplugged from the RAL shaping amplifier, and so plugged these back in. I then repeated the walkthrough.

The second pulser walkthrough was saved as: Remote_Objs/RData_1/180220172838

Like the first walkthrough, the pulser ampltudes were 0.1, 0.2, 0.3, 0.4, and 0.5 V.

A sample pulser walkthough spectrum is attached.

The pumps were left on overnight, in the morning at 8:25 the pressure reads:

Up = 1.5e-5 mBar and Down = 4.0e-5 mBar.

We made a first attempt at collecting an alpha spectrum for the far S2 detector using ADC 2 and ADC 3. However ADC 3 appeared to be acting as a TDC for no obvious reason.

During this attempt we noticed ADC 2 channels 0, 1, and 5 had a high rate, and ADC 2 channel 8 had a low rate.

We moved the ribbon inputs on ADC 3 to ADC 4, the spectra on ADC 4 looked better. ADC 4 Channel 30 had a low rate.

We noticed ADC 3 was still active -> removing the ribbon inputs had no effect on the module writing to the DAQ. We raised the lower threshold of ADC 3 to 2046 (total 2047 channels), effectively stopping it from writing.

The thresholds for ADC 2 and ADC 4 were set to channel 40 for both. The thresholds on the RAL shaping amplifiers are set to 15mV.

At 9:09 we started collecting an alpha spectrum for a preset time of 900 seconds, finishing at 9:24. The dead time was 24% and the event multiplicity 3.2 (event mult. was 40 before removing ADC 3). The trigger rate was ~9kHz. The data were saved in /RemoteObjs/RData_1/180220091352/

To try and lower the trigger rate I removed the 6th breaker in the top IDC convertor box, which corresponds to the 5th channel of RAL I, which in turn corresponds to the 5th channel of ADC 2.

The trigger rate had risen (strangely) to ~12kHz, we saw ADC2 CH 0 had a high rate.So I removed the 1st breaker in the top convertor box, which corresponds to the 0th channel of RAL I, which in turn corresponds to the 0th channel of ADC 2.

Now the trigger rate was ~9kHz, with a good event rate ~ 40 Hz. We agreed that since the preamp box does not have its cover on there will be noise, particularly from the turbo located immediately downstream from the preamp box.

At 11:30 we started trying to tune the beam. Before sending beam I moved the target ladder to position 95.010mm, achieved by first moving the actuator to position 96mm and then back in position to account for backlash.

Note: All the target ladder calibration points were obtained by moving the ladder towards the actuator.

By 12:44 we were still tuning. We obtained a beam current of 200pA in FC-0, the faraday cup located ~1m upstream from the chamber, however we were unable to find the beam downstream from the chamber.

We were using the 3mm diameter blank frame for beam tuning, and decided to now attempt tuning with the 10mm blank frame.

We were using the only blank 10mm target frame available to support the alpha source, so we decided to vent the chamber and move this to an accesible part of the target ladder for beam. This would also allow us to inspect the beamline and check it is clear of obstruction with the telescope.

We switched off the detector and vented the chamber. I then removed the target ladder and switched the 10mm blank frame holding the alpha source with a 3mm blank frame. The 10mmblank frame was attached at position 2 of the ladder.

See attached (IMG_2709.jpg) for the first target ladder setup. See attached (IMG_2712.jpg) for the new target ladder setup.

We set the target ladder to 80.024mm for the 10mm blank frame, and then using the telescope confirmed it was in the beam axis. This involved removing the upstream lid and putting a piece of white paper in.

We then sealed the chamber and at 14:40 started the roughing pumps. The gate valve was cracked open -> we want a pumping speed <10mBar/s to avoid damaging the detectors and/or mylar foils.

At 15:04 the gate valve was fully opened and the turbos started. By 15:12 the pressures read: Up = 9.2e-5mBar, and Down = 1.0e-4mBar. The detector was biased at -130.3V with a leakage current 1.19uA.

With no beam the DAQ trigger rate ~ 6kHz.

At 15:29 we started the beam tuning with the 10mm blank frame in the beam axis.

During tuning the power supply on the 1st analysing magnet, located between the cathode source and accelerator, showed problems and was replaced.

At 17:50 I checked the S2 leakage current = 1.28 uA. The slight rise from 1.19 uA could be due to temperature fluctuations (8 degrees temp increase causes factor 2 difference)

At 18:20 we decided to vent the chamber and shine a light upstrean from the faraday cup FC-0. After switching off the detector and venting the chamber we discovered the piece of paper used to check the 10mm aperture alignment was left inside the upstream section of the chamber since the last time we vented. No beamspot was seen on the paper.

At 19:00 we restarted the roughing pump and cracked open the gate valve. At 19:03 the turbos were started. At 19:06 the pressures read Up = 7.0e-5, Down = 1.3e-4 mBar. The S2 was biased back to -130.3V, leak current = 1.20 uA.

We went back to tuning (third time today). With no beam we had a DAQ trigger rate ~ 2.6kHz, event multiplicity = 10.

We were able to see beam on FC-0, but unable to see beam on either of two faraday cups located downstream of the chamber. We decided to check the beamline again.

At 20:40 the detector was switched off. The turbos were then switched off. At 21:00 a tiny amount of air was allowed into the chamber to help slow the turbos, by 21:05 they were <12Hz. We vented the chamber.

After inspection of the beamline we discovered a new cause of the tuning problem. A small piece of mylar was in the bellow located downstream from FC-0. See attached IMG_2724.jpg.

We inspected the 12um mylar in front of the S2, it was not damaged, suggesting the rogue piece of mylar from the bellow is from a previous experiment.

We removed the rogue mylar and remounted the bellow to the beamline, we confirmed it was aligned using the telescope. We had a clear line of sight through the beamline, suggesting the problem is solved.

We declared victory.

At 22:30 we started the roughing pump for the section of beamline upstream from FC-0.

(Note: Tom Davinson is now in CIRCE until the 21st)

On 19/02/2018 we performed the following:

This morning we gave CIRCE technician Antonio slanted spacer boxes (for mounting preamps) and also the Al box (used for target ladder) for minor modifications

I needed to unmount the Al box from the target chamber. As I did so some air rushed in as I unmounted the box, indicating the chamber was not back at atmosphere from pumping on Friday.

I also removed the central lid with the iris attached. I discovered the iris was broken beyond repair. We will need to order a new one and some spares.

Learning note: To avoid damage always have irises fully opened when pumping down the chamber.

In the meantime Tom D has been wiring up the rest of the electronics setup. He discovered the CAMAC crate was not supplying any voltage. We removed the crate and double checked the connection between the rear power box and the crate – it was not fully screwed in on the bottom. After fixing this we remounted the CAMAC and found all voltages read out correctly, including a current readout of -10A at the -6V voltage.

Next we set out to vacuum test the chamber. In total today we performed four vacuum tests.

In each test the diode mount, lemo feedthrough, 64-way vacuum feedthrough, and an iris mounts were installed in the central section (the iris mount in the central chamber had no iris due to damage mentioned above). The iris mount with an iris (fully opened) and 64-way vacuum feedthrough were installed in the downstream section. The Al spacer box for the target ladder was also installed, however the target ladder was not because Antonio was not finished with modifications. Instead of the target ladder a blank flange was installed. The two actuators for opening and closing the irises were also installed in the central and downstream chamber sections.

The first two vacuum tests showed a high leak rate, high 10^-4 mBar even without helium injected close to the chamber.

In the first test we found the two 64-way vacuum feedthroughs were causing a leak, after venting the chamber these were removed and mounted flat to the lid using four bolts, one at each feedthrough corner. We then started the second test.

In the second test we discovered a leak was caused by the lemo vacuum feedthrough on the central lid. After the test we put additional grease on the o-ring and around the flange section of the feedthrough (atmosphere side) to help it seal.

On the third vacuum test after ~ 20 minutes of running the up and downstream turbos the pressures levelled to:

Up = 3.6e-4 mBar, down  = 3.4e-4 mBar

We then switched off the turbos and continued monitoring the vacuum. After ~30 minutes from turning off power to the turbos, they had completely stopped spinning, the pressures read:

Up = 6.5e-1 mBar, down = 6.5e-1 mBar

We found during this test the lemo feedthrough was still not sealing, and in addition neither was the Al spacer box for the target ladder.

After venting we found a hair on the lemo feedthroughs o-ring. The hair was removed and additional grease was applied to the o-ring and lid. We also confirmed the nut was tight. For the spacer box we found the bolts used were slightly too long, and so removed ~ 2mm from the threads. The box was then remounted and looked flush with the side of the chamber.

After this test at ~16:00 Antonio had finished and delivered both the modified spacer boxes for the preamps and the target ladder mounting box, now it correctly uses a 16mm centering ring.

We then started the fourth vacuum test, now with the target ladder actuator mounted too (as well as all the other parts from tests 1-3):

At 16:43 the roughing pump in the leak test was started. At ~16:50 the turbos were started, both up and downstream from the chamber.

At 17:04 (~15 minutes later) the pressures in the chamber read: Up = 3.1e-4 mBar, Down = 2.8e-4 mBar.

We declared victory for the vacuum and decided to mount the detectors and an alpha source.

On the central lid we mounted the Si diode with 0.9um mylar and a 1mm collimator at ~28 degrees rotation (relative to the central lid) -> currently this is performed using an angle measuring app on my android phone and one screw, so this angle selection needs to be better reproducible for the future.

We discovered there was no way to mount the S2 detector on the central lid -> either the legs of its connectors collide with the lid, or when the iris mount is rotated 180 degrees (moves detector slightly upstream) the iris then collides with the target ladder. The way we mount the detector on the central lad needs redesign -> I will take the central lid with irises and diode mount back to Edinburgh to address and fix this problem. I can also use this opprtunity ot find a better mounting procedure for the Si diode.

We did mount the S2 2323-18 (496um) detector to the downstream iris mount. 12um mylar was placed in front with a central hole of max width <20mm to allow the beam to pass trough.

On the target ladder we mounted an alpha source at position 5mm. The alpha source specifications are:

Type: EAX

Prod No: 111109-1242002

Radionuclide: 241Am + 239Pu

Activity: 8.153 kBq

Reference Date: 25/3/2010

At 20:49 with the single S2 detector, diode detector and the alpha source mounted in the chamber we started the roughing pumps.

At 20:54 we started the turbos, including not only the up and downstream turbos but also the large turbo located below the chamber. The pressures read: Up = 1.3e-4 mBar, Down = 1.5e-4 mBar.

We went to dinner. Raffaele had fish.

22:19 The pressures read: Up = 1.4e-5 mBar, Down = 3.7e-5 mBar

We mounted the preamp box on top of the chamber with preamp 2 inside. The cables for the detector bias, +15 and -15V preamp power, +ve pulser, and ribbon signal cables were connected.

Biasing the S2 to -130V we read a leakage current = 1.16 uA. Powering the preamp we read currents: V=+15V -> I = 0.9A, and V=-15V -> I = 0.4A, as expected. The pressures read: Up = 1.4e-5 mBar, Down = 3.2e-5 mBar

Using DSO we observe

• RAL 1 CH 0->7 pulser OK, no alpha
• RAL 2 CH  0 no pulser or alpha
• RAL 6 CH 1->7 pulser OK,  no alpha
• RAL 8 CH 6 no alpha, pulser not connected to n+n ohmic strips

We declared today a good day and left the lab.

This morning whilst I was setting up the ribbon cabling (see eLog entry #8) I was considering collecting a voltage bias vs leakage current curve for one/two of the S2 detectors, depending on time available.

This would involve using the central section of the chamber and the straight spacer box to mount the preamp on top of the lid.

Note: we currently cannot use the angled spacer boxes for the chamber yet, because these need to be trimmed by Antonio (the technician) to allow more space for the ribbon cables and also allow the box to sit flat on top of the vacuum feedthrough. We will be seeing Antonio on monday morning to prioritise required machine work.

However, I then remembered that after we stopped the pumps last night we did not vent the chamber. This morning at 10:52 the labview program used to control the pumps read the following pressures:

• Turbo Up 1 = 1000mBar
• Turbo Up 2 = 389mBar
• Turbo Down 1 = 86.1mBar
• Turbo Down 2 = 49.7mBar
• Chamber Up = 1000mBar
• Chamber Down = 139mBar

I emailed Lucio to see if he could come in this weekend to vent the chamber and we could then mount and test two of the S2 detectors, one after the other. Otherwise we can do this monday morning.

As an aside there is some serendipity here, the pressures I read this morning indicate if there is a leak in the chamber it is more likely to be found upstream.

Between 9:00 to 12:30 this morning Filipo was working on the weekend 14C measurements, allowing me to work in the lab during this period.

I unpacked four MALU 4532 Lecroy Logic Modules (sent to CIRCE two weeks ago). Three of these modules were installed into the 1434A CAMAC crate, which already had one module installed from the July 2017 shift. One module remains out of the crate as a spare.

I connected 16 way - 16 way ribbon cables between the front of both IDC converter boxes to the back of the RAL shaping amplifier modules. They are connected as follows:

• RAL shaping amps I, II, XI, and IV are connected to top convertor box inputs 0->3, counting from the left when facing the rack
• RAL shaping amps V, VI, VII, and VIII are connected to top convertor box inputs 4->7
• RAL shaping amps X, XII, XIII, and "R" are connected to bottom convertor box inputs 8->11
• RAL shaping amps "S", "Q", "u", and "W" are connected to bottom convertor box inputs 12->15

In second electronics rack, "Rack B", at the top is a Nim bin used last July 2017 for the Si diode.

In this nim bin I installed two NIM-ECL-NIM converters and the PB-5 Pulser Generator

Currently in the Nim bin from left to right we have the following:

1. Silena mod 7710 Quad Bias Supply
2. Ortec 571 Amplifier
3. Ortec 863 Quad TFA
4. Ortec 935 Quad CFD
5. Two ECL-Nim-ECL Converters, Model EC1600 by EG&G-ESN
6. Lecroy Model 622 Quad Coincidence Unit
7. PB-5 Pulse Generator

The Nim bin was switched on in this configuration, I checked the supplied voltages with a voltmeter. All voltages, -6, +6, -12, +12, -24, and +24V read correctly.

Next I installed 5m 34 way - 34 way ribbon cables labelled 0, 1, 2, and 3 into the back of the top convertor box, including the grounding cable. Now:

• Cable 0 in back splits into cables 0 and 1 in front
• Cable 1 in back splits into cables 2 and 3 in front
• Cable 2 in back splits into cables 4 and 5 in front
• Cable 3 in back splits into cables 6 and 7 in front

Next I installed 5m 34 way - 34 way ribbon cables labbeled 13, 14, 15, and 16 into the back of the bottom convertor box, including the grounding cable. Now:

• Cable 13 in back splits into cables 8 and 9 in front
• Cable 14 in back splits into cables 10 and 11 in front
• Cable 15 in back splits into cables 12 and 13 in front
• Cable 16 in back splits into cables 14 and 15 in front

The other end of these eight 5m long cables are ready to be plugged into the EDI preamps

I then plugged 16-way ribbon cables into the Analogue Output of the RAL shaping amplifiers in the following order, where ADC ... is the label of the cables:

• RAL I -> ADC 8A
• RAL II -> ADC 8B
• RAL XI -> ADC 9A
• RAL IV -> ADC 9B
• RAL V -> ADC 10A
• RAL VI -> ADC 10B
• RAL VII -> ADC 11A
• RAL VIII -> ADC 11B
• RAL X -> ADC 12A
• RAL XII -> ADC 12B
• RAL XIII -> ADC 13A
• RAL "R" -> ADC 13B
• RAL "S" -> ADC 14A
• RAL "Q" -> ADC 14B
• RAL "u" -> ADC 15A

Some of the RAL "W" Analogue pins were slightly off center. Filipo needed to leave so I left cable ADC 15B unplugged.

I attach photos of the current status of both electronics racks

By 16:40 I mounted all three chamber lids.

The central chamber lid includes the diode detector mount, the iris, a vacuum feedthrough, and an actuator with no hook.

The downstream chamber lid includes a vacuum feedthrough and an actuator with no hook.

I then mounted the target holder actuator with its two aluminium boxes.

I noticed the sides of the boxes were not trimmed down since my last visit in July 2017. So again I needed to remove washers from the bolts directly below these boxes, which are used to connect the beamline and turbo sections of the target chamber. I also noticed the hole of the aluminium box which the target actuator arm sits was not enlarged since my last visit, and so is not large enough to fit a standard 16mm o-ring centering ring. Instead a smaller centering ring is used which means the actuator arm is not centered, for the vacuum tests this isn't a big problem.

Note: when I mounted the target actuator I replaced its 80mm (total length) Al tube with the 60mm (total length) Al tube, this should allow access to all target positions.

After some further setup on the beamline - including checking the turbo pumps were being water cooled - we were ready to start the vacuum test.

At 18:00 we started the roughing pumps

At 18:10 we started the two upstream and two downstream turbo pumps

At ~18:18 the chamber up and chamber down readings were at low 10^-4 mBar, we would've expected lower pressure readings due to the power of the pumping system. We suspected a leak and switched off the pumps.

Lucio noticed the 70mm screws mounting the lids and collar to the rest of the chamber were too long, and either needed to be shortened or additional washers used - otherwise we could heavily damage the chamber thread

At the end of the day we learnt Fillipo will be in the lab tomorrow (saturday 17th) between 9:00 - 13:00, and agreed that I (Thomas C) could come in and connect the electronics cables ready for next week.

After lunch we were still having problems with the aperture hook, see first attached image highlighting the arm is located in close proximity (but not touching) the vacuum feedthrough and ribbon cable.

Meanwhile in Edinburgh Peter Black designed and built an additional component of the hook to assist in connecting it between the actuator and iris arms, see second attached image.

I decided enough time had been spent on this so far and to go ahead with testing the chamber vacuum.

This morning we moved the electronics rack to within ~2.5m of the target chamber, leaving room for the ribbons cables of ~5m length which connect the preamps to the amplifiers in the rack.

Then I continued in attempts to solve the iris arm problem, see eLog entry #3.

When comparing to the CAD drawing (entry #4) David pointed out the iris was mounted the wrong way around, and that it should be rotated 180 degrees. I attempted this yesterday but decided to investigate more thoroughly.

I made three changes in total:

1. I replaced the lemo cable on the Si diode with a shorter one (~7.5mm) from Edinburgh, reducing the chance to catch the lemo between the lid and chamber wall

2. I moved the diode mount away from the upstream chamber wall to be certain there was no collision here

3. I removed the nylon screws intended to connect the S2 to the nylon standoffs on the iris

After each change I reattempted mounting the central lid with the iris attached, after the third correction it fit! This suggested the nylon screws were slightly too long.

I measured the thickness of the S2 detector serial no 2323-18:

PCB board thickness = 2mm

Yamatchi connector thickness = 8mm

Bond wire solder thickness on back of S2 ~1mm

The thread of one nylon screw was cut from 6mm to 4.5mm, after screwing this back onto the iris standoff I found the lid still fit onto the chamber. There will be enough thread to still mount the S2's.

At ~13:20 we then went to lunch

Find attached the latest CAD diagram of the Target Chamber, drawn by Peter Black

After lunch we attempted to connect the actuator arms to the iris arm used to change the iris diameter. We need two iris diameters: fully open for experiment measurements and a 5mm diameter for beam focusing

To do this the original design uses a cuboid with two rods, one rod is connected to the actuator arm, and the other rod is connected to the iris arm with a hook - see attached. The rods were first cut down to fit into the chamber. This would allow us to change the iris diameter whilst under vacuum.

We decided to first check we could connect the hook to the iris in the central section of the target chamber, because this has the most amount of access space. We mounted the iris onto the bottom of the central lid using it's two legs.

After several attempts we could not find a suitable position for the hook and box combination, for several reasons:

1. The cuboid used to hold the metal hook will hit the iris legs at the limits of the actuator arms movement. This means the iris cannot be completely opened or closed. We could close the iris until a diameter of 13mm is left, however the active region of the S2 detectors starts at ~11.5mm diameter so this will not work when focusing the beam.

2. Also if we mount the hook facing upwards (above the cuboid) it is too high to reach the iris arm

3. If we rotate the hook such that it faces downwards (below the cuboid) it now reaches the iris arm. However, the hooks height needs to be adjustable because the iris arm moves vertically as the iris is opened and closed. This is currently not possible as the hook cannot be loosed without falling into the chamber

Note: when the iris is fully opened or closed its arm is at its furthest vertical distance from the chamber lid. When the iris is halfway between open (or closed) its arm is at its closest vertical distance from the chamber lid.

We noticed the cuboid used to hold the two rods is assymetrical and so attempted switching around the two rods, this did not solve the problem.

We then attempted a simpler solution: We replaced the cuboid and two rods with two long screws placed directly in the actuator arms threaded holes, see second attached photo.

The idea being that we can simply move the iris arm with these two screws - there will be some backlash to this technique because the distance between the two screws is larger than the diameter of the iris arm. This should not be a problem because we will only need two positions.

However we found the screws still collide with the iris legs close to the limits of the iris arm movement.

Most importantly: We realised that either the hook or screw technique will both hit the ribbon cable connecting the detector to the vacuum feedthrough, see attached sketch

The central collar of the chamber does have a second position for the actuator arm, however this will hit the Si diode we intend to use to measure the backscattered beam. So this will not work.

At 18:30 we decided to leave the lab and sleep on this problem.

The only solution seen so far is to focus the beam with no detectors mounted. Then after focusing is complete: vent the chamber, mount the detectors, repump the chamber down to vacuum, and remount the preamplifiers on top of the chamber. This would not be optimal but it may be a temporary fix until a better solution is found.

This morning both myself and Raffaele mounted the beamline section of the target chamber.

We also mounted the turbo located immediately downstream from the target chamber, see attached IMG_2621.jpg image - the beam will enter from the right of the image

We then mounted the collar section of the target chamber.

We mounted the two linear actuators onto the collar section, which are used to open and close the iris apertures.

These apertures will be essential to stop the beam during beam focussing

Attached is a report summarising work performed on the electronics and target chamber in CIRCE from the 10th to the 22nd July 2017.

Outstanding problems have also been listed.