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