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.