Minutes of Bcal Readout June 18 2009

[Elton Smith <elton@jlab.org>]

= Minutes =
Attending: JLab: Elton, Beni, Sasha, Eugene, USM: Alam, George, Will,
Pedro; UofR: Andrei

# Announcements
# Review of Action Items
# USM report
##
[http://www.jlab.org/Hall-D/software/wiki/images/6/6b/DLO_v0.1_-_Resume.pdf
Pedro's presentation]
##* Added GlueX-doc-1291 and requests feedback
##* Started from GlueX-doc-1279, and studied optimization of pmt positions
in the field. Determined that the optimal angle is 27.3 deg based on the
gain sensitivity to the B-field over 2 degree interval.
##* Used 'Solid Works' 3-D cad system to place PMTs at a nominal location
of 30 deg relative to the field. Elton: noted that the location of the
calorimeter relative to the field was shifted and this needs to be
updated.
##* It is great to see that the USM has some of these modeling tools which
will be very useful in laying out light guides for FM pmts.
##* JLab should send files from I-deas that can be imported into their cad
system.
# Prototyping
# Fibers
#* Acceptance of first shipment. Decided to accept current batch of fibers
but verify npe numbers with further measuremnts.
#* Delivery of second shipment. Respond to Kuraray with acceptance of
proposed July 1 date for second delivery.
# Discussion of readout options
## FM light guides (See updated
[http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=1287
GlueX-doc-1287])
##* New acceptance studies have been included into the GlueX note. In
summary, the long FM light guides collect less than half the light of the
SiPMs.
## [http://clasweb.jlab.org/elton/halld/temp/eltonbcalreadout.pdf
Mechanical model] (by Hutton)
##* First look at the two options: FM (outer) + SiPM (inner) and all FM
pmts. We will require iterations to clarify some issues especially related
to the cooling options for SiPMs.
# Bcal Readout Review (July 21). Elton has sent out a draft proposal to a
few people for initial feedback.
## Stefano Miscetti will participate via video
## Other reviewers: Suggested ask Stepan if he would be willing to
participate in review
##* Will: The choice involves evaluating a "off-the-shelf" option with
limitations to a "risky" option with little track record. Thus the choice
is one of judgement and it might be worth including somebody with project
management experience in the review.
## Tentative agenda
# Simulations
## [http://www.jlab.org/~somov/bcal_light.ppt Background from Cerenkov
light ] (Sasha)
##* Geometry for studies has been setup. Studies of background will be
sent out shortly.
## Andrei will complete simulations of number of visible photons per GeV.
##* Has produced a new file at 2 GeV and 20 deg.
##* Beni: Noted that the showers are produced (over a 1 cm impact
position) at the center of the module. This may limit the range of
energies deposited in each cell. We requested a 2 GeV, 20 deg shower but
with impact positions at the center of a cell (i.e offset from the center
of the module itself). This might be useful for dynamic range studies.


Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
(757) 269-6331 fax