GlueX PID Meeting, October 1, 2010
Contents
Location, Time
Friday, October 1, 2010
2:00 pm EDT
JLab: CEBAF Center, Room F326/7
ESNet: 8542553
EVO: direct meeting link
Conference Group: 800-377-8846, participant code: 77438230
Slides: talks can be deposited in the directory /group/halld/www/halldweb1/html/talks/2010-10 on the JLab CUE (you have to be a member of the "halld" group). This directory is accessible from the web at https://halldweb1.jlab.org/talks/2010-10/ .
Agenda
- Announcements
- Minutes from the last meeting
- Time-of-Flight
- Prototype Status
- Calibration system
- Mechanical interface to support structure: real estate planning
- MOU status
- Start Counter Status
- MOU plans
- Target
- Refrigerator update
- MOU status
- Action Items
Minutes
Present:
- FSU: Sasha Ostrovidov
- JLab: Eugene Chudakov, Mark Ito (chair), Elton Smith, Sascha Somov, Simon Taylor, Beni Zihlmann
TOF Prototype Studies
Sasha reported on progress at FSU.
Time Resolution
He has done new time resolution tests with the new Hamamatsu PMT's. To do this back to use the CAEN constant-fraction discriminators. With the new tubes at two voltages:
| Voltage (V) | Resolution (ps) | Comment |
|---|---|---|
| 1750 | 140 | recommended voltage |
| 2000 | 114 | maximum voltage |
Compare this to the previous best measurement with the old Hamamatsu tubes at 2000 V of 124 ps.
These tests were done with Tyvek wrapping. When ESR was tried, at the higher voltage, the resolution was 112, not much improvement. Tests were also done with a 50-50 signal split. Resolution came out at 116 ps, very little effect.
beni: worry about running pmt's at maximum voltage request for lifetime estimate, lifetime usually quoted in terms of charge
Splitters
fernando has sent 2 splits and 2 inverters to fsu
new production lab, cleaning it, furnishing it
Beni: resolution goes linear with light output
tuning the constant fraction
have not gone to new trigger paddles
using new data acquition system
with leading edge discriminator: no timewalk correction 180 ps
(t1 - t2)/2
Plans
FSU MOU
Paul sent new language , Elton put it in, will send to Glenn and Allison, liability language
