GlueX Start Counter Meeting, March 21, 2019
- Review minutes from the last meeting
- Calibration and Efficiency
- SiPM dark rate measurement
- NIM Paper
- Action Item Review
Talks can be deposited in the directory
/group/halld/www/halldweb/html/talks/2019 on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2019/ .
- JLab: Sean Dobbs, Mark Ito (chair), Simon Taylor, Beni Zihlmann
The Start Counter NIM paper has been published. The record in JLab's publication database has been updated as has the GlueX wiki's list of publications.
Review minutes from the meeting on February 7
We went over the minutes. Sean plans to talk to Mahmoud Kamel about the status of the comparison between data and Monte Carlo.
SiPM dark rate measurement
Beni has analyzed data taken under the following conditions
- read-out threshold set below pedestal
- read-out of all SiPM detector systems (start counter, BCAL, etc.)
- random trigger at 2 kHz
- raw mode
He integrates over all samples and normalizes to the number of events. Histograms are fit to a Gaussian from the low side to just over the peak on the high sides. The idea is to count events in the high-side tail of the distribution. The data from two runs are shown. The red points were taken in the middle of the Beryllium target run, the blue points are from yesterday. He showed some representative channels from the start counter.
He believes that there is an effect seen, but more analysis is needed.
Beni wants to talk to Carl Zorn about what expectations for dark rate are. Also he has yet to look at other detector systems.
He also mentioned that there is a procedure to anneal the SiPM to partially cure an elevated dark rate due to neutron radiation damage. We could consider this if the damage is severe.