[Halld-pid] Minutes, GlueX Start Counter Meeting, September 22, 2011

[Mark M. Ito]

Folks,

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Start_Counter_Meeting%2C_September_22%2C_2011#Minutes 
and below.

-- Mark
_____

GlueX Start Counter Meeting, September 22, 2011

Minutes

Present:
* FIU: Werner Boeglin, Puneet Khetarpal, Lei Guo, Eric Pooser
* JLab: Eugene Chudakov, Chuck Hutton, Mark Ito (chair), Tim
Whitlatch, Beni Zihlmann


Prototype Testing

Eric has been looking at more of the scintillator pieces from Plastic
Craft. They have poor surface quality and an attenuation length 4 times
worse than when they arrived from Eljen. He is getting a time
resolution in the range 230 ps to about 600 ps, going from the upstream
end out to the nose. He is using the SiPM as a detector, with no light
guide. All of the pieces will be assessed, shipped back to Plastic
Craft for resurfacing, and then re-tested.

Mechanical Design

Tim has been trying hand-layouts of the SiPM's. If the SiPM's are
packed side-by-side inside the CDC, then only 24 can be accommodated.
He is also looking at a staggered arrangement (alternate SiPM's offset
upstream and then downstream). Also if the light guides can be made 60
centimeters (roughly) long, then any azimuthal segmentation is OK (say
30 or 40). Going to 24 counters will increase the per counter rate
which was estimated by Sasha and Seema at about 200 kHz for 40
counters, with the nose going down to 2 cm radius, at 10^8 γ/s

Eugene wondered whether we don't need to bring the SiPM's out from the
CDC bore in order to place them farther from the beam line and in a
more benign radiation environment.

Eugene also asked about the thinking on using scintillating fibers. The
plan now is to continue with the scintillator paddles and think about
an upgrade with the fibers.

Simulation

Puneet has started working with the simulation. He showed
proof-I-have-started plots of generated distributions, occupancy, and
deposited energy. See [25]his plots for details.

MOU

The changes suggested by FIU to the draft approved by the Concurrence
Chain were passed by Rhonda Scales and Allison Lung at JLab. They had
no further suggestions, so Werner will proceed with collecting
signatures at FIU.

Retrieved from 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Start_Counter_Meeting%2C_September_22%2C_2011

References

25. https://halldweb1.jlab.org/talks/2011-3Q/puneetk/