[Halld-pid] Minutes, GlueX TOF Meeting, December 12, 2011

[Mark M. Ito]

Folks,

Find the minutes at 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_December_12,_2011 
and below as text.

-- Mark
_____

GlueX TOF Meeting, December 12, 2011

Minutes

Present:
* FSU: Paul Eugenio, Sasha Ostrovidov
* JLab: Eugene Chudakov, Chuck Hutton, Mark Ito (chair), Simon
Taylor, Beni Zihlmann

Announcements

* Chuck received the of new light guide design. Looks good.
* Paul is ready to try cutting the VM2000 for light guide wrapping.
Chuck will send him a 2-D projection of the light guides to serve
as a template.
* Paul will look into getting large sheets or rolls of the VM2000
again.

Trip Report: Work at FSU

Beni reported on work he, Sasha, and Paul did during Beni's recent trip
to FSU (November 28 through December 2). He led us through [31]his wiki
page summarizing the work. He described:
* cosmic ray test stand at FSU
* PMT gain measurements
* revised PMT current estimates
* time difference resolution measurements

Most encouraging, he gets a Δt/2 resolution of 80 ps near the center of
the TOF prototype.

We agreed that the trip was very useful and will help with
communication in the future.

Prototype Tests

Sasha showed progress in the last week with the prototype. See his
[33]web page for details. He showed:
* improvement in trigger counter time difference measurements after
Paul changed the phototubes
* improved separation between pedestal and signal in the TOF
prototype paddle with a longer ADC gate

PMT Choice

We discussed the various option for the PMT purchase. Beni agreed to
summarize the arguments and proposals and send them out to the list.

Attaching the PMT's

We discussed various ways of attaching the PMT's to the light guides in
light of the need to replace tubes in the future if rates are what we
expect.
* optical glue (epoxy?): Paul is using this now. He reports success
separating the PMT's from the light guides and re-establishing good
optical contact.
* optical grease: easy to detach the tube, harder to support
mechanically
* optical cookie: same comment
* RTV: Eugene reported a good experience using this with lead glass
blocks and PMT's. Strong glue joint and easy damage-free un-gluing.

Clearly, we need to study the various options. Eugene will send Paul
information on the RTV so that he can try that.

Contract

Mark outlined the next steps for FSU to develop a proposal for the
contract:
* Construction Manual
* Quality Assurance Plan/Acceptance Procedures
* Construction Schedule

We also discussed the importance of having a Construction Manager to
oversee day-to-day operations. Paul said that he already had someone in
mind who has experience with detector construction for high-energy
experiments.

Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_December_12,_2011"

References

31. https://halldweb1.jlab.org/wiki/index.php/Test_Stand_at_FSU
33. 
https://halldweb1.jlab.org/talks/2011-4Q/PMT%20change%20and%20ADC%20gate.html