Difference between revisions of "GlueX TOF Meeting, January 10, 2017"
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GlueX Time-of-Flight Meeting<br> | GlueX Time-of-Flight Meeting<br> | ||
| − | Tuesday, | + | Tuesday, January 10<br> |
11:00 am EST<br> | 11:00 am EST<br> | ||
| − | JLab: CEBAF Center, Room | + | JLab: CEBAF Center, Room B101 '''non-standard room''' |
==Agenda== | ==Agenda== | ||
# Announcements | # Announcements | ||
| − | # Review of [[GlueX TOF Meeting, | + | # Review of [[GlueX TOF Meeting, December 13, 2016#Minutes|minutes from the previous meeting]] |
| − | + | # [https://logbooks.jlab.org/entry/3448871 Lucite Shield Results] (Paul) | |
| − | # [https://logbooks.jlab.org/entry/ | + | # [http://hadron.physics.fsu.edu/wiki/index.php/Photomultiplier_tubes PMT Testing] (Paul) |
| − | #[http://hadron.physics.fsu.edu/wiki/index.php/Photomultiplier_tubes PMT Testing] (Paul | + | |
| − | + | ||
# NIM Paper (Paul) | # NIM Paper (Paul) | ||
# Action Item Recap | # Action Item Recap | ||
| Line 23: | Line 21: | ||
Talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2016</code> on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2016/ . | Talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2016</code> on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2016/ . | ||
| + | |||
| + | ==Minutes== | ||
| + | |||
| + | Present: | ||
| + | |||
| + | * '''FSU''': Paul Eugenio | ||
| + | * '''JLab''': Thomas Britton, Brad Cannon, Mark Ito (chair) | ||
| + | |||
| + | === Lucite Shield Results === | ||
| + | |||
| + | Paul led us through [https://logbooks.jlab.org/entry/3448871 his logbook entry] (shown below) tabulating the results of the test of a Lucite shield for the counters closest to the beamline. Data were taken at the end of the Fall run. Substantial rate reduction was observed with the TOF discriminator scalers. For example, the 2.25 inches of Lucite (17% of a radiation length) reduced the rate in S:21 by about 35% and that in S:22 by about 45%, independent of the beam rate used in the measurement. | ||
| + | |||
| + | [[Image:TOF-Shield-Study-Fall2016-4.png|800px]] | ||
| + | |||
| + | We concluded that the Lucite would not do harm to the TOF measurement and gives a substantial rate reduction, reducing the current load on the last dynode of the PMTs. The hypothesis is that low energy electrons and positrons are getting ranged out in the additional shielding. Now that a significant effect has been observed, the next step is to see what a Monte Carlo study says. Pending results of that study, the proposal is to leave the configuration of shielding used in the study in place for the next run. It appears to be doing more good than harm. | ||
| + | |||
| + | === PMT Testing === | ||
| + | |||
| + | Paul drove the 25 PMTs to be tested down to FSU. Five were retained at JLab for studies. Ashley Ernst, an FSU grad student, will execute [http://hadron.physics.fsu.edu/wiki/index.php/Photomultiplier_tubes the testing procedure]. | ||
| + | |||
| + | === PMT Voltage Scan Analysis === | ||
| + | |||
| + | Brad has been hampered in his efforts by the Lustre disk problems at JLab. This remains work in progress. | ||
| + | |||
| + | === Collaboration Meeting === | ||
| + | |||
| + | Brad will give the TOF report at the upcoming meeting. | ||
Latest revision as of 11:30, 11 January 2017
GlueX Time-of-Flight Meeting
Tuesday, January 10
11:00 am EST
JLab: CEBAF Center, Room B101 non-standard room
Contents
Agenda
- Announcements
- Review of minutes from the previous meeting
- Lucite Shield Results (Paul)
- PMT Testing (Paul)
- NIM Paper (Paul)
- Action Item Recap
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/2016 on the JLab CUE. This directory is accessible from the web at https://halldweb.jlab.org/talks/2016/ .
Minutes
Present:
- FSU: Paul Eugenio
- JLab: Thomas Britton, Brad Cannon, Mark Ito (chair)
Lucite Shield Results
Paul led us through his logbook entry (shown below) tabulating the results of the test of a Lucite shield for the counters closest to the beamline. Data were taken at the end of the Fall run. Substantial rate reduction was observed with the TOF discriminator scalers. For example, the 2.25 inches of Lucite (17% of a radiation length) reduced the rate in S:21 by about 35% and that in S:22 by about 45%, independent of the beam rate used in the measurement.
We concluded that the Lucite would not do harm to the TOF measurement and gives a substantial rate reduction, reducing the current load on the last dynode of the PMTs. The hypothesis is that low energy electrons and positrons are getting ranged out in the additional shielding. Now that a significant effect has been observed, the next step is to see what a Monte Carlo study says. Pending results of that study, the proposal is to leave the configuration of shielding used in the study in place for the next run. It appears to be doing more good than harm.
PMT Testing
Paul drove the 25 PMTs to be tested down to FSU. Five were retained at JLab for studies. Ashley Ernst, an FSU grad student, will execute the testing procedure.
PMT Voltage Scan Analysis
Brad has been hampered in his efforts by the Lustre disk problems at JLab. This remains work in progress.
Collaboration Meeting
Brad will give the TOF report at the upcoming meeting.
