General Meeting Summary 10/22/15

MEETING WITH RAINER IN GIESSEN

Last 40 crystals Rainer received (produced in summer 2015) had good light yield and were radiation hard. However, slow component increased to 10% and almost all crystals fail transmittance requirements at all wavelengths. Worry is that doping resulted in increased light yield, but may have had other negative effects on the crystal growth process.
30 crystals were received at JLab in early October 2015. The company provided results on transmittance and light yield, which look ok overall. No details on crystal production process or the transmittance and light yield measurements were included. Action item: measure crystal properties.

Discussion on CRYTUR status

The company is making good progress and Rainer has received another full-size crystal in early October 2015. He is planning to order a set of pre-production crystals over the next year.
IPN-Orsay received a quote from Crytur (2000 euro/crystal) and will order 3 crystals for testing. Together with crystals available from Rainer this should give a big enough sample for conclusions on quality and possible prototype tests

Discussion about EU proposal submission for development of high quality PWO crystals

Follows up on a previous proposal, but with modified scope and collaborating institutions
Submission due date is end of October

PLANNING FOR CRYSTAL TESTING

For specifications table include a description of what drives each specification and how they are to be measured

Draft a plan on which tests will be done for the 30 SICCAS crystals, what institutions will perform them, how many crystals will be tested at each institution, and what the expected logistics/timeline will be.

IPN-Orsay: transmittance with Varian photospectrometer, light yield (temperature control?), exploring options for irradiation
Giessen: transmittance with modified Varian photospectrometer, light yield with temperature control to better than 1 degree Celsius, irradiation with Co-60
CUA: transmittance with Perkin-Elmer photospectrometer, light yield with temperature control to 1 degree Celsius, exploring options for irradiation (e.g., with Xray system)
JLab: transmittance with optical setup including an integrating sphere

NPS MAGNET

SBS used steel from the BNL 48D48 magnets. Need to check if this steel would also be suitable for the NPS magnet

COLLABORATION MEETING: 21 JANUARY AT JLAB (time: TBD)

existing thoughts to make the best optimal photon source needed for the approved polarized WACS experiment, but perhaps also beneficial for other already approved proposals
updates on the progress with crystal tests/selection procedures
update on magnet design
update on PMT HV divider
possibiliites for Timelike-Compton Scattering measurements with photon beam, NPS and polarized target in Hall C
...

ITEMS FOR NEXT MEETING:

NEXT MEETING: THUR 12 NOVEMBER, TIME: 9:00 AM (EDT)

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