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 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.

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: 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

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

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

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

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 ^_^

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

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.

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

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.

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 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 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 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 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 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