[Halld-cal] Minutes from Cal Working group meeting.

[Elton Smith]

=Minutes=

''Attendees: Will, Serguei (USM at CERN); Elton, Beni, Fernando, John,
Lubomir, Eugene (JLab); Zisis, Andrei (UofR).

# Announcements
# Review of Action Items
# FCAL
## Notes from Matt: Excellent news on the CW front
##* Paul has a new reel of caps that hold voltage to 3 kV in air (leads
soldered directly to to cap).
##* Under the microscope these look better than old caps -- less "spikey
stuff" on the metallization.
##* He fully assembled one multiplier board and powered it up to 2 kV.  It
held 2 kV fine without any conformal coating.
# Calibration
#* No update, but calibration of Bcal should receive a higher priority in
future meetings.
# BCAL
## Construction Status
##* Mid-month report submitted yesterday. A flake of epoxy got stuck on
one of the presses denting a small area at layer 80.
##* Modules 19 and 20 up to 100 layers.
##* ROSS machining has started on 17 and 18 even before 19 and 20 have
arrived.
##* Shipment 13-16 picked up at noon. Should arrive tomorrow. Will check
for confirmation.
# Light guides
##* Will asked about Athens measurements of WC vs USM guides. Zisis said
that illumination was not very uniform during tests and they are trying to
improve that. Preliminary measurements showed that the trapezoidal/WC ~
0.8 - 1.0.
# SiPM update
#* Yi is preparing 1x1 mm2 samples for irradiation and recovery at
different temperatures. The plan is to irradiate them between now and
Monday.
#* (Fernando) Carl is measuring the uniformity across the face of one
irradiated and one non-irradiated array.
# Simulations
# Other Updates
## Will: Internal discussions are in progress regarding the
statement-of-work. Will send Elton/Eugene updates with questions to
further this along.
## Will asked if there was any feedback to Alam's presentation at the
collaboration meeting.
##* Elton asked if there were any further updates on the mechanical box
and environment control. Will indicated that the design has been simplfied
but concept remains. Serguei mentioned that CAEN HV supplies (3 modules
with 16 channels each) for the SiPM have been ordered. The ammeter they
will use has 10 nA accuracy.
## Eugene inquired about LHC studies for using SiPMs. Serguei is meeting
with CMS personnel (Ian and Yuri?) and will get the latest information.
They are purchasing 2000 3x3 mm2 units for pre-production testing of the
units for the external calorimeter. They are looking for substitutes for
the hybrid pmts and APDs. The APDS are generating spikes in response to
neutrons (prob ~ 10^-3) and are generating single-tower signals as input
to the trigger, which is problematic. These problem of spikes is
compounded because they are using a single amplifier for two APDs
## Serguei mentioned that 700 Pb-glass blocks of size 40x40x400 mm3 are
available from experiment WA98(?). GlueX needs radiation hard blocks.
Serguei will see if any are available.


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