Readout box
We use a readout box made by Hans. It supplies the bias to nine SiPMs and amplifies the signals. It needs to be connected to 70V power supply, and a +-6V power supply for the amplification. The wiring scheme is available, and also printed in the lab. You can find more information in this file File:Readout solutions for VULCAN.pdf
Note: channel 4 or channel 6 is disabled because of a short. It will need to be fixed in the future.
New readout box:
We had a range of issues with the old readout box (noisy, unpredictable and generally difficult to work with) and then many channels died over time due to unknown causes. Thus, we have to redesign/improve the readout such that we can have a stable solution.
List of general requirements:
- Noise: < 10% of 1 photoelectron peak amplitude (rough estimate).
- Dynamic range: 1-10 photons
- 9 independent channels that can be turned on/off as needed
Things to improve from old box design:
- Random amplifier oscillations
- Minimize signal shape degradation due to amplification stage (stretching in time, moving baseline, negative undershoot..)
- Better cabling/shielding inside the box between channels to reduce interference between channels
- Better way to bias SiPM without risk of affecting amplification stage
- Reducing pick up of high frequency noise when connected with the vacuum chamber
Other related things:
- We currently identify SiPM cathode/anode by looking at current drawn by SiPM -> extra effort of closing/opening box, risk of drawing too much current. Need some way to label the kapton wires.
- We are currently soldering kapton wire to SiPM -> better solution?