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