HV adjustment
High Voltage adjustment software
Following procedure should be applied in order to determine correct voltages settings for HAND scintillators. During the summer and fall 2010, measurements of gain curves for HAND scintillators were performed in Testlab. Due to the lack of delay cables, electronic units, fastbus crates etc. The measurements were spit in groups of 12 (out of 112). Almost all measurement were done with same electronics (amplifiers, discriminators...). However, In the Hall we will be using different cables and different electronics. This can cause some disagreement with the measured gain curves. In addition because of different enviromental conditions gain curves may be shifted by hundred Volts or even more.
For this reason following software was prepared. The Algorithm for using this script is following:
- Perform short cosmic runs when all scintillators connected to DAQ. The trigger for this run should be OR between all bars. Alternatively these runs can be done for every layer seperatly.
- From 4 runs calculate the gain curves using two scripts: adc.C and curves.C. This procedure should be performed layer by layer (the scripts can be extended for all HAND, however because we can't check it, it's better to perform in this way.
- Calculate the desired voltages for each scintillator based on the Gain Curves.
- Take a measurement with the calculated voltages.
- Find the ADC peaks (punch through or elastic).
- Run this script with updated information for the included scripts.
- Apply the new voltages, and check the ADC channel.
- Make additional iterations if needed
