Difference between revisions of "GlueX PID Meeting, May 28, 2010"

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** Paul discussed using a passive splitter with Fernando Barbosa at the last collaboration meeting. We should discuss all options further.
 
** Paul discussed using a passive splitter with Fernando Barbosa at the last collaboration meeting. We should discuss all options further.
  
−
==
+
==Reviewing minutes from the last meeting==
  
−
pulse tube refrigerator for target, lab review helium demand
+
We went over them.
−
tim reported on solenoid and pulse tube refrigerator
+
−
frost target
+
−
expectation
+
−
hydrogen, deuterium and helium 4
+
−
chris claimed it was possible
+
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no resources in target
+
−
relatively low load compared to other hallds
+
−
already moved money to buy thing
+
  
−
1. calibration
+
Tim mentioned a recent meeting where there was a lab-wide review of helium demand in the future. At the meeting he mentioned the idea of getting a pulse tube refrigerator for target and our needs for the solenoid. Others at the meeting raised the possibility of supporting various other types of targets, include a FROST target. We agreed that for now our planning should only include hydrogen, deuterium and helium 4; other possibilities would have to be raised and developed before impacting current plans. The change request to support a purchase has been approved.
−
time-walk studies, laser data
+
−
received led from nitchia, uv and blue, circuit constructed, use uv to excite scintillator, cable constructed,
+
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working on scope, 8 ns min width, 5 V
+
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wheel? continuous variation
+
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might be hard for calorimeter system to vary amplitude
+
  
−
2. change of thickness of counters
+
==Time-of-Flight==
−
want to increase to match end of pmt, 1 in to 1-1/3 in. talked to Matt, little effect on calorimeter, still 6 cm wide
+
  
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-> study light collection
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We went over several items.
 +
 
 +
===calibration===
 +
 
 +
Paul reminded us that in Hall B, time-walk studies are done with a laser pulsing system. To explore doing similar studies ourselves, he has received LED's from [http://www.nichia.co.jp/en/about_nichia/index.html Nichia], both UV and blue. A circuit has been constructed to drive the LED's. The UV LED will be used to excite the scintillator. He is working with a scope right now. He can get down to 8 ns width and 5 V pulse height with the pulser he has.
 +
 
 +
We had originally discussed using the system being developed for the calorimeter to pulse the TOF. There was some concern about whether that system could vary output amplitude precisely enough to calibrate the time-walk.
 +
 
 +
===change of thickness of counters===
 +
 
 +
Paul proposed that we increase the thickness of the TOF counters to better match the size of the photocathode of the PMT, from 1 in. to 1-1/3 in. He has talked to Matt, who thought that there would be little effect on calorimeter. The width would remain the same at 6 cm.
 +
 
 +
There was some discussion about how much might really be gained. We probably should try to understand the limits to light collection in either plan.
  
 
3.
 
3.
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# Arrange a meeting to discuss signal splitting schemes for the TOF PMT signals.
 
# Arrange a meeting to discuss signal splitting schemes for the TOF PMT signals.
 +
# Think about light collection studies for the TOF.

Revision as of 09:33, 1 June 2010

Location, Time

Friday, May 28, 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/2010-05 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/2010-05/ .

Agenda

  1. Announcements
  2. Minutes from the last meeting
  3. Time-of-Flight
    1. Calibration: variation of pulser amplitude for time walk correction measurement
    2. Change in thickness of TOF counters?
    3. Status of PMT purchase (for prototype testing)
    4. Electronics: signal split scheme (no dynode signal)
    5. Prototype progress
    6. Status of the MOU
  4. Start Counter
    1. prototype progress: attenuation length measurements
  5. Target
    1. Status of the MOU
    2. Status of refrigerator plan
  6. Action Items

Minutes

  • FSU: Paul Eugenio, Sasha Ostrovidov
  • JLab: Eugene Chudakov, Mark Ito (chair), Sascha Somov, Tim Whitlatch, Elliott Wolin, Beni Zihlmann
  • UMass: Rory Miskimen

Announcements

  • Eugene announced that the recent change request approved has been approved and we can go ahead and buy some PMT's for the TOF prototype.
  • This generated some discussion:
    • Paul reported that Hamamatsu has offered to put a dynode output on the base for same price as for the standard configuration. He reminded us that the original plan was to use an XP2020 with both anode and dynode outputs.
    • Paul discussed using a passive splitter with Fernando Barbosa at the last collaboration meeting. We should discuss all options further.

Reviewing minutes from the last meeting

We went over them.

Tim mentioned a recent meeting where there was a lab-wide review of helium demand in the future. At the meeting he mentioned the idea of getting a pulse tube refrigerator for target and our needs for the solenoid. Others at the meeting raised the possibility of supporting various other types of targets, include a FROST target. We agreed that for now our planning should only include hydrogen, deuterium and helium 4; other possibilities would have to be raised and developed before impacting current plans. The change request to support a purchase has been approved.

Time-of-Flight

We went over several items.

calibration

Paul reminded us that in Hall B, time-walk studies are done with a laser pulsing system. To explore doing similar studies ourselves, he has received LED's from Nichia, both UV and blue. A circuit has been constructed to drive the LED's. The UV LED will be used to excite the scintillator. He is working with a scope right now. He can get down to 8 ns width and 5 V pulse height with the pulser he has.

We had originally discussed using the system being developed for the calorimeter to pulse the TOF. There was some concern about whether that system could vary output amplitude precisely enough to calibrate the time-walk.

change of thickness of counters

Paul proposed that we increase the thickness of the TOF counters to better match the size of the photocathode of the PMT, from 1 in. to 1-1/3 in. He has talked to Matt, who thought that there would be little effect on calorimeter. The width would remain the same at 6 cm.

There was some discussion about how much might really be gained. We probably should try to understand the limits to light collection in either plan.

3.

4.

discussion of different wrapping material, now using tyvek, some aluminized mylar and aluminum foil vm2000 now called esr df2000ma, originally sold as roll, Yuri got some, primex used it. start counter for clas used it, planning on using it for clas12 tof. not sold in rolls anymore, lcd screens current market, sample obtained, 20 ft, 1.5 ft wide, fool around with it. will test different materials, cost: roll $1000 150 ft. thickness: 2.6 mils non conductive, non magnetic, reflectivity 99% black tedlar for wrapping, dupont says can't get it, will get sample 6ft by 150 ft.

5. prototype progress paddles machined down to 6 cm wide

6. status of the MOU focusing on DOE proposal question of overhead, off campus rate on doe grant, off = 26%, on = 46% may want to wait on MOU

-> last mods by tue of next week

Rory has sent MOU to jlab

New Action Items

  1. Arrange a meeting to discuss signal splitting schemes for the TOF PMT signals.
  2. Think about light collection studies for the TOF.
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