[Halld-cal] Minutes of Bcal Readout Meeting

[Elton Smith]

= Minutes =
Attendees: Eugene, Beni, Yi, John, Elton,  (JLab), Andrei, Zisis (Regina);
Will (local), Alam (USM); Zisis, Andrei (UofR);

# Announcements
# Review of Action Items
## Will to find out if there is any feedback from USM on terms and
conditions from our procurement package.
##* An agreement was reached between the Basal Grant and the university
(USM) that the grant will carry any risks associated with accepting JLab
procurement condtions. This is allow procedures to move forward at
contract time. This agreement was reached at the time the MOU was signed.
# [[SiPM Radiation Hardness Test]]  (Update from Yi)
## The wiki page has been reorganized, and plots have been updated with
corrections factors for the neutron probe.
## The estimated lifetime of SiPMs at this time is about 8-9 calendar
years (at 10^8/s). However, this estimate includes an extension of the
lifetime of a factor of 2 (annealing) and additional factor of 3 for
running at 5deg C. Both factors will be checked on irradiated samples when
new samples are received from Hamamatsu in a couple of weeks. (Yi will
remind Hamamatsu that the schedule for receiving the samples is very
important to us).
## Data files from Carl has allowed Yi to fit for the dark rate.
##* Increase in dark current is consistent with the dark rate. Also, the
estimated cross talk is extracted and about 13-15%.
##* Gain of samples remains unchanged.
##* The revised estimate for the dark rate of "outlier" 1x1 mm2 sample
irradiated in Hall A gives a factof of 2.4 larger rate than other samples.
This is lower than originally estimated. (Note that the plots on the wiki
page used different pre-amplifer factors for the three plots, which is
indicated in the comments).
## Carl will measure the variation of dark current across the irradiated
arrays to check for uniformity. This is waiting on electronics from
Fernando?
# Update - USM
## SiPM test stand (Alam)
##* Electronic (bare) boards for testing the dark current and SiPM signals
have been fabricated (visually verified on video). Each board will allow
readout all cells (16 chanels) from one array. (Alam could you verify this
number?)
##* Boards need to stuffed (~1 week). Major components are in hand, some
additional connectors can be added later.
##* The boards will check that signals (first with oscilloscope, later
with ADC).
##* The boards will then check that accurate measurements of dark current
can be made (requires careful control of environment, humidity, etc)
##* Adjustments to the boards may be necessary before producing more
boards.
## Status of statement of work (SOW)
##* No update.
# Electronics/cooling
#* no update
# Geometry and light guides
#* no update
# Simulation runs
#* Computer runs have been completed (reported at previous meeting) and
results are being used in the analysis of CR data
# Cosmic-ray setup at UofR
#* All data taking has been completed. Fitting of center point has been
performed, but a combined fit to all data sets is in preparation. DeltaE
from 2x2 area yields about 12x more light than single fiber, yielding
about 10-11 times higher yield than single fiber. Assuming a 90%
transmission of light guides, a preliminary conclusion is that the module
light output is consistent with extrapolations from single-fiber
measurements. Analysis is being finalized, will be reported next week at
the cal WG and/or at the collaboration meeting.
# [[GlueX-Collaboration-Sep-2010 | Collaboration Meeting]] (Five 25-min
sessions allocated), some topics... Elton will propose time allocations
for discussion next week at the cal WG.
#* SiPM report
#* Bcal construction
#* Cosmic-ray measurements (Andrei)
#* Fcal construction
#* Update on Bcal reconstruction
#* Comparison of light transmission of light guides (Athens)
#* Preparations at USM
#* Decisions: Fcal insert, monitoring/calibration



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