Difference between revisions of "GlueX/Primex 2008-06-04"

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(Preamble)
(Preamble)
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* Calibration procedure for the crystals needs to be considered.  The plan is to hang a Plexiglas sheet in front of the lead-glass crystals and inject light into the sheet.  Can this technique be made to work with PrimEx design or is something more sophisticated needed?
 
* Calibration procedure for the crystals needs to be considered.  The plan is to hang a Plexiglas sheet in front of the lead-glass crystals and inject light into the sheet.  Can this technique be made to work with PrimEx design or is something more sophisticated needed?
 
* What is the optimal z alignment for the shorter lead-tungstate blocks?  Moving the blocks to align with the upstream face of the lead glass will certainly enhance shower leakage at the boundary.  Aligning with the downstream face increases the distance between the ToF and calorimeter which is likely to significantly degrade resolution for photon that preshower in the ToF.
 
* What is the optimal z alignment for the shorter lead-tungstate blocks?  Moving the blocks to align with the upstream face of the lead glass will certainly enhance shower leakage at the boundary.  Aligning with the downstream face increases the distance between the ToF and calorimeter which is likely to significantly degrade resolution for photon that preshower in the ToF.
 +
* What are the temperature and humidity stability requirements of lead-tungstate?
 
* What is the schedule for availability of the PrimEx lead-tungstate crystals and how does this fit into the construction schedule for the FCAL?
 
* What is the schedule for availability of the PrimEx lead-tungstate crystals and how does this fit into the construction schedule for the FCAL?
  

Revision as of 15:08, 3 June 2008

Meeting Time and Place

The meeting will be on Wednesday June 4, 2008 at 1:30pm EST. For those people at Jefferson Lab, the meeting will be in room L102/104

Meeting Connections

To connect from the outside:

1.) ESNET:

   Call ESNET Number 8542553 (this is the preferred connection method).

2.) Phone:

  +1-800-377-8846 : US
  +1-888-276-7715 : Canada
  +1-302-709-8424 : International
   then enter participant code: 39527048# (remember the "#")

Preamble

I will start this with the assumption that we would all like to move forward on integrating the efforts of members of PrimEx with GlueX. In addition, we also need a detailed discussion of of what needs to be modified in GlueX to be able to facilitate PrimEx running.


I see this latter issue as having several component. The first has to do with the highest photon energy that can be tagged, and with what accuracy this can be done. Richard has looked at some of these issues and I believe that they have been presented in the beam line/tagger working group. There is also the issue of possibly using some existing PrimEx beam line instrumentation in GlueX. If this is desirable, then we need to understand what the schedule for availability of this equipment would be and understand how its installation in Hall D would fit into the overall installation schedule. Included in this discussion is also the pair spectrometer, and what the most effective way of doing that is.


We also have the issue of the GlueX FCAL and can we use some or all of the PrimEx lead-tungstate crystals in in the inner part of the FCAL. Here, there are a rather large number of issues.

  • Simply supporting the lead-glass wall would require either a new support structure or a shift to something similar to the PrimEx stacking procedure. Matt Shepherd has been looking at this at IU, but I am not sure we know the change of scope yet.
  • The readout of the smaller lead-tungstate crystals needs to be examined in light of the non-zero magnetic field in GlueX. Can the current PrimEx readout be made to work in this region, or does something else have to be defined?
  • Calibration procedure for the crystals needs to be considered. The plan is to hang a Plexiglas sheet in front of the lead-glass crystals and inject light into the sheet. Can this technique be made to work with PrimEx design or is something more sophisticated needed?
  • What is the optimal z alignment for the shorter lead-tungstate blocks? Moving the blocks to align with the upstream face of the lead glass will certainly enhance shower leakage at the boundary. Aligning with the downstream face increases the distance between the ToF and calorimeter which is likely to significantly degrade resolution for photon that preshower in the ToF.
  • What are the temperature and humidity stability requirements of lead-tungstate?
  • What is the schedule for availability of the PrimEx lead-tungstate crystals and how does this fit into the construction schedule for the FCAL?


We should also discuss other areas of interest that might be mutually of interest.

Agenda

  • Beamline issues
    • pair spectrometer
    • tagging range and resolution
    • equipment from PrimEx
    • manpower
  • FCAL issues
    • availability of lead-tungstate (timelines)
    • readout of lead-tungstate in a magnetic field
    • manpower
  • Other issues

Minutes