[Halld-pid] Time-of-Flight Meeting Minutes, February 13, 2014

[Mark Ito]

Folks,

Find the minutes below and at:

https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_February_13,_2014#Minutes 
.

-- Mark
________________________________________________________________________

GlueX TOF Meeting, February 13, 2014
Minutes

Present:
* FSU: Paul Eugenio, Sasha Ostrovidov, Aristeidis Tsaris
* JLab: Eugene Chudakov, Chuck Hutton, Mark Ito (chair), Tim
Whitlatch, Beni Zihlmann

Review of meeting on January 30

We looked over the [22]minutes.
* Beni is finishing the changes to the TOF geometry to incorporate
the half-width counters. In addition, he has consolidated
hard-coded constants into a single place in the code.
* Mark mentioned that he had inadvertently omitted from the minutes
the discussion of a TOF fast-shutdown mechanism that we had last
time. We had concluded that the built-in safeguards of the CAEN
high-voltage supplies are sufficient protection for the TOF.

Collaboration Meeting

Sasha will give the TOF update at the Collaboration Meeting.

Installation Update

Paul gave the report.
* The studs were all brought back to FSU and the machining of middle
sections is complete. They are all packaged up and ready for the
return trip to JLab.
* Paul will bring up a holding frame for repairing the two counters
whose glue joints (between the light guide and scintillator) broke
during the installation dry-runs. The frame was made from parts
from the gluing fixture used during module construction. The plan
is to hang the frame and modules from the forward platform. Eljen
EJ-500 two-component epoxy is used.
* Paul was planning to come up just before the collaboration meeting
and do the repairs over the the weekend, but Tim told us there is a
power outage planned for the entire Hall on that Saturday and
Sunday, so that plan will have to be adjusted.
* Tim reported that the clamps to compress the entire array have come
in.
* Tim also reported a plan to add foam pieces in the spaces where the
aluminum cheese pieces were to have gone originally, as a
mechanical backstop in case there is any slippage in the clamping
channels. There was some discussion about the need for foam in this
area. When Paul gets to the Lab he and Tim will review the plan.

Calibration

Sasha is enhancing capabilities of his stand-alone Monte Carlo. He is
generating pπππ events and matching x and y planes using the TOF alone.
For two-tracks in the TOF, he gets the matching wrong 15% of the time;
for three tracks, 40% of the events have matching mistakes. He is
working on improvements. Mark suggested that at some point Sasha might
consider doing studies with HDGeant where charge particle tracking
would help.

Testing Modules in the Hall

* Hussein has found a few light leaks in the first layer. He is
simply looking at rates on the scope with a single PMT.
* Paul was planning on bringing another HV supply channel to enable
triggering on one end and looking at the other, but Beni told us he
has a four channel supply that they can use. Beni will get together
with Hussein on this.

Retrieved from
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References

22. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_January_30,_2014#Minutes