Difference between revisions of "GlueX PID Meeting, July 9, 2010"

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(Miutes: who was there)
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[http://evo.caltech.edu EVO]: [http://evo.caltech.edu/evoNext/koala.jnlp?meeting=eaeDetvavnaDaiasIa direct meeting link]<ref>This link is good through 8/20</ref><br>
 
[http://evo.caltech.edu EVO]: [http://evo.caltech.edu/evoNext/koala.jnlp?meeting=eaeDetvavnaDaiasIa direct meeting link]<ref>This link is good through 8/20</ref><br>
 
Conference Group: 800-377-8846, participant code: 77438230<br>
 
Conference Group: 800-377-8846, participant code: 77438230<br>
'''Slides''': talks can be deposited in the directory <code>/group/halld/www/halldweb1/html/talks/2010-07</code> 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/2010-07/ .
+
'''Slides''': talks can be deposited in the directory <code>/group/halld/www/halldweb/html/talks/2010-07</code> on the JLab CUE (you have to be a member of the "halld" group). This directory is accessible from the web at https://halldweb.jlab.org/talks/2010-07/ .
  
 
=Agenda=
 
=Agenda=
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# [[Time-of-Flight/Start-Counter Action Items|Action Items]]
 
# [[Time-of-Flight/Start-Counter Action Items|Action Items]]
  
=Miutes=
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=Minutes=
  
 
'''FSU''': Sasha Ostrovidov
 
'''FSU''': Sasha Ostrovidov
 
'''JLab''': Eugene Chudakov, Mark Ito (chair), Yi Qiang, Sascha Somov, Elton Smith, Tim Whitlatch, Elliott Wolin, Beni Zihlmann
 
'''JLab''': Eugene Chudakov, Mark Ito (chair), Yi Qiang, Sascha Somov, Elton Smith, Tim Whitlatch, Elliott Wolin, Beni Zihlmann
  
cryo review, tim still needs to do this, cost estimate needed as well
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==Review of minutes from last meeting==
chris confident about He4, but need verification
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chris was going to talk to vendor
+
  
LED pulser system up running, not yet tried with counter
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We went over the [[GlueX_PID_Meeting%2C_June_11%2C_2010#Minutes|minutes from June 11 meeting]].
used for time walk corrections for time-of-flight
+
useful but a lot of effort
+
could it have been done with the data, but difficult
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data does not have a start time
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need to have the scintillator excite
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Elton down at USC, similar things being done for CLAS12
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===PMT purchase for TOF prototypes===
they decided against a laser system, will do everything with data
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with cosmic ray set up they got time-walk correction
+
we will have two planes, that will help
+
large dynamic range in energies needed
+
if it can be done from the data, the calibration system will not be done
+
need a study
+
  
Flash ADC would be desireable at some time.
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The PO went out. Paul Eugenio is waiting on delivery.
time difference idea: Yi
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trapezoidal light guide not large enough to cover PMT
+
===Refrigerator for the target===
  
new data acquisition system written, not used yet
+
* Tim still needs to do the cryo review. A cost estimated is needed as well.
doing measurements with different wrappings want to keep set-up constant
+
* Chris Keith is confident about the <sup>4</sup>He capability of the proposed refrigerator, but this needs verification. Chris was planning to talk to the vendor about this.
  
40 cm long trigger counters
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===Time-of-flight prototype===
  
cosmic ray measurements using different
+
Sasha O. reported that the LED pulser system up and running, but has not yet been tried with the prototype counters.
pedestal reduction program, 400-> 200 counts
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adjustment on ADC
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3 days to collect statistics
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new material ESR/VM2000, mylar to come
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then switch to new daq and led pulser
+
  
Ralf using aluminized mylar, works well in Germany
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===Need for a laser calibration system for the time-of-flight===
want a stable material
+
CLAS6 used aluminum foil
+
  
Eugene
+
Elton reported on the use of a nitrogen laser in CLAS for calibration of their time-of-flight system. It was only used for for time-walk corrections and was useful but a lot of effort was necessary to build, install, and maintain the system. Time-walk corrections could have been measured with the data, but would have been difficult since the data does not have a explicity external start time. He pointed out the need to choose a frequency so that the scintillator itself is excited.
use pair spectrometer, change pair spectrometer magnet to vary opening angle, solenoid will move pairs around
+
acceptance: small opening angle to get through beam tube
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2 cm target, vacuum chamber
+
  
 +
Elton was recently down at the University of South Carolina. Ralf Gothe there is doing similar things for the CLAS12 forward TOF. They have decided against a laser system; they will do everything with the data. With their cosmic ray set up they have obtained time-walk correction constants.
 +
 +
Elton pointed out that we will have two planes, and that will help doing the calibration with the data. A large dynamic range in energies needed. There was a lot of discussion about possible data-based calibration schemes. Clearly a study of a particular scheme or schemes is needed. If a workable scheme can be proposed, then we may not need a calibration system as elaborate as that used by CLAS.
 +
 +
===Other TOF issues===
 +
 +
* Sasha mentioned that tests with a flash ADC would be desirable at some time.
 +
* The trapezoidal light guides are not large enough to cover PMT. That frustrated the first attempt to measure the response of the edges of the PMT's.
 +
* The new data acquisition system using the TI is written; it has not been tested yet.
 +
 +
==Time-of-flight prototype progress==
 +
 +
Sasha O. has been working on cosmic ray measurements using different wrapping material for the prototype counters. He showed [https://halldweb.jlab.org/talks/2010-07/ADC%20spectra%20with%20different%20wrappings.html plots of the ADC spectra] for materials tried so far. Future plans include aluminized Mylar and ESR DF2000.
 +
 +
Elton mentioned that at USC, Ralf is using aluminized Mylar. That worked well for Ralf on a previous experiment. Elton also mentioned that CLAS uses aluminum foil to wrap their counters.
  
 
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Latest revision as of 11:35, 31 March 2015

Location, Time

Friday, July 9, 2010
2:00 pm EDT
JLab: CEBAF Center, Room F326/7
ESNet: 8542553
EVO: direct meeting link[1]
Conference Group: 800-377-8846, participant code: 77438230
Slides: talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2010-07 on the JLab CUE (you have to be a member of the "halld" group). This directory is accessible from the web at https://halldweb.jlab.org/talks/2010-07/ .

Agenda

  1. Announcements
  2. Minutes from the last meeting
  3. Time-of-Flight
    1. Prototype progress [1]
    2. Status of the MOU
  4. Start Counter
    1. prototype progress
  5. Target
    1. Status of the MOU
    2. Status of refrigerator plan
  6. Action Items

Minutes

FSU: Sasha Ostrovidov JLab: Eugene Chudakov, Mark Ito (chair), Yi Qiang, Sascha Somov, Elton Smith, Tim Whitlatch, Elliott Wolin, Beni Zihlmann

Review of minutes from last meeting

We went over the minutes from June 11 meeting.

PMT purchase for TOF prototypes

The PO went out. Paul Eugenio is waiting on delivery.

Refrigerator for the target

  • Tim still needs to do the cryo review. A cost estimated is needed as well.
  • Chris Keith is confident about the 4He capability of the proposed refrigerator, but this needs verification. Chris was planning to talk to the vendor about this.

Time-of-flight prototype

Sasha O. reported that the LED pulser system up and running, but has not yet been tried with the prototype counters.

Need for a laser calibration system for the time-of-flight

Elton reported on the use of a nitrogen laser in CLAS for calibration of their time-of-flight system. It was only used for for time-walk corrections and was useful but a lot of effort was necessary to build, install, and maintain the system. Time-walk corrections could have been measured with the data, but would have been difficult since the data does not have a explicity external start time. He pointed out the need to choose a frequency so that the scintillator itself is excited.

Elton was recently down at the University of South Carolina. Ralf Gothe there is doing similar things for the CLAS12 forward TOF. They have decided against a laser system; they will do everything with the data. With their cosmic ray set up they have obtained time-walk correction constants.

Elton pointed out that we will have two planes, and that will help doing the calibration with the data. A large dynamic range in energies needed. There was a lot of discussion about possible data-based calibration schemes. Clearly a study of a particular scheme or schemes is needed. If a workable scheme can be proposed, then we may not need a calibration system as elaborate as that used by CLAS.

Other TOF issues

  • Sasha mentioned that tests with a flash ADC would be desirable at some time.
  • The trapezoidal light guides are not large enough to cover PMT. That frustrated the first attempt to measure the response of the edges of the PMT's.
  • The new data acquisition system using the TI is written; it has not been tested yet.

Time-of-flight prototype progress

Sasha O. has been working on cosmic ray measurements using different wrapping material for the prototype counters. He showed plots of the ADC spectra for materials tried so far. Future plans include aluminized Mylar and ESR DF2000.

Elton mentioned that at USC, Ralf is using aluminized Mylar. That worked well for Ralf on a previous experiment. Elton also mentioned that CLAS uses aluminum foil to wrap their counters.


Footnotes

  1. This link is good through 8/20