Difference between revisions of "GlueX TOF Meeting, November 3, 2015"
From GlueXWiki
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Talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2015</code> on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2015/ . | Talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2015</code> on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2015/ . | ||
+ | |||
+ | ==Minutes== | ||
+ | |||
+ | Present: | ||
+ | * '''FSU''': Hussein Al Ghoul, Brad Cannon, Sasha Ostrovidov, Aristeidis Tsaris | ||
+ | * '''JLab''': Mark Ito (chair), Simon Taylor | ||
+ | |||
+ | ===Calibration with Cosmics=== | ||
+ | |||
+ | Sasha gave a report on recent work. | ||
+ | |||
+ | * He has succeeded in taking cosmic data, but had a couple of difficulties: | ||
+ | *# He needed to attempt to start runs several times before getting any triggers at all. He suspects that with multi-block readout of the CAEN TDCs, the token passing between modules would stop, hanging the system. | ||
+ | *# ROCTOF1, which houses the FADCs, would crash in minutes from the start of the run. A hard reboot was needed to get things going again. | ||
+ | *#* This problem has resolved itself recently. | ||
+ | ** In the end he got a few times 100 k events. | ||
+ | * The trend of higher gains at the edges of the arrays seen in beam data is also seen in cosmic data. | ||
+ | ** This rules out the magnetic field, or a systematic problem using beam tracks. | ||
+ | ** Possible culprits: | ||
+ | *** Different HV supplies than those used at FSU. | ||
+ | *** Different HV cables. | ||
+ | ** He is working on a program to adjust HV to equalize gains. Data will be taken, gains measured, HV adjusted, and process iterated. | ||
+ | ** He is also seeing a difference in the gain when comparing a hit in the middle of the paddle versus one near the ends, even after accounting for attenuation. The gain is about 10% higher near the ends. | ||
+ | * He is trying to judge the effect of gain calibration using a set of "tracks" in the TOF in cosmic data. He requires 5 counters minimum. The yield of such events is extremely low, about one part in ten thousand. | ||
+ | ** The trigger rate is about 600 Hz. | ||
+ | ** The threshold for a single FADC channel to be read out is 500 counts. The trigger threshold on the sum is about 50,000 typically, but other values have been tried. | ||
+ | |||
+ | ===Calibration=== | ||
+ | |||
+ | * Brad is in contact with Sean Dobbs about a plug-in to be used in the calibration challenge. | ||
+ | * He is also cleaning up the script to drive the calibrations already done. |
Revision as of 21:58, 4 November 2015
GlueX Time-of-Flight Meeting
Tuesday, November 3, 2015
11:00 am EST
JLab: CEBAF Center, Room F326/327
Agenda
- Announcements
- Review of minutes from September 22
- Calibration Status FSU
- Calibration Status JLab
- NIM Article
Communication
- The BlueJeans Meeting number is 350 531 998.
- Enter BlueJeans Meeting
Slides
Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2015
on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2015/ .
Minutes
Present:
- FSU: Hussein Al Ghoul, Brad Cannon, Sasha Ostrovidov, Aristeidis Tsaris
- JLab: Mark Ito (chair), Simon Taylor
Calibration with Cosmics
Sasha gave a report on recent work.
- He has succeeded in taking cosmic data, but had a couple of difficulties:
- He needed to attempt to start runs several times before getting any triggers at all. He suspects that with multi-block readout of the CAEN TDCs, the token passing between modules would stop, hanging the system.
- ROCTOF1, which houses the FADCs, would crash in minutes from the start of the run. A hard reboot was needed to get things going again.
- This problem has resolved itself recently.
- In the end he got a few times 100 k events.
- The trend of higher gains at the edges of the arrays seen in beam data is also seen in cosmic data.
- This rules out the magnetic field, or a systematic problem using beam tracks.
- Possible culprits:
- Different HV supplies than those used at FSU.
- Different HV cables.
- He is working on a program to adjust HV to equalize gains. Data will be taken, gains measured, HV adjusted, and process iterated.
- He is also seeing a difference in the gain when comparing a hit in the middle of the paddle versus one near the ends, even after accounting for attenuation. The gain is about 10% higher near the ends.
- He is trying to judge the effect of gain calibration using a set of "tracks" in the TOF in cosmic data. He requires 5 counters minimum. The yield of such events is extremely low, about one part in ten thousand.
- The trigger rate is about 600 Hz.
- The threshold for a single FADC channel to be read out is 500 counts. The trigger threshold on the sum is about 50,000 typically, but other values have been tried.
Calibration
- Brad is in contact with Sean Dobbs about a plug-in to be used in the calibration challenge.
- He is also cleaning up the script to drive the calibrations already done.