Page History

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11:10
Linac back again.
10Hz, 120MeV, ~fC (estimation)
180V bias, see a ~10uA leakage current. This doesn't chance when beam goes on/off.
We observe large, ~400ADC, sample to sample shifts when using external trigger.
When beam is turned off we still see ~100ADC sample to sample shifts.
Everything looks ok with software trigger with beam on/off.
We turned off the RF equipment (X- and S) in the tunnel and that brought the noise back to 35-40ADC. Looks like there was some interference. There are many things that are exposed: 5m long power, incl. bias, wires running along floor, devboard on floor 1m below beam line and ~1m from dump. This only happened on external trigger and due to time constraints we decided to go on with our program and forget about timing in.
PLOTS OF SHIFTS FOR THE DIFFERENT CONDITIONS

11:36
Starting radiation program. There was no way we could measure anything below ~1pC so we start the program from there.:

• Start with 6 foils
• Beam energy: 120MeV, 10Hz, bunch charge 1pC
• Start at 180V bias voltage on sensor
• 30s-60s of exposure to beam at each setting of bias voltage and bunch charge
• Run baseline at each setting and a baseline at 180V for each setting to be able to compare.
• Wrote down the measured leakage current from the bias supply. It takes quite some time for it to settle so the measured values fluctuates a lot. After many runs the 180V leakage was consistently at 5uA every time we came back to it.

Runs taken, all at 6 foils:

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