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.