General Meeting Summary 11/12/15

CRYSTAL TESTING FACILITIES

• Discussion about available facilities

• IPN-Orsay: Transmittance (L&T, Ocean Optics fiber-based spectrometer with support structure, Varian Cary 5000), irradiation with source (Co-60, pointlike, 30Gy in 30 min), Light Yield with cosmics
• Giessen Univ: Transmittance (L&T, Varian Cary 5000, reproducibility ~0.1%), Irradiation with source (Co-60, uniform, 30 Gy in 10 min, room temperature), Light Yield with source (temperature control to 0.1 deg)
• CUA/CU: Transmittance (L&T, Perkin-Elmer Lambda 750, reproducibility ~0.2%), irradiation option with Xrays (Faxitron CP-160, energy range up to 160 kV), Light Yield with Na-22 source (temperature stabilization better than 1 degree)
• Caltech: Transmittance (L&T, Perkin-Elmer Lambda 950, reproducibility ~0.2%), irradiation with source (Co-60 for 2-30 rad/hr, Cs-137 for ~7000 rad/hr - sources pointlike?), Light Yield with Cs-137 source (systematic uncertainty 1%)
• JLab: Transmittance (L&T, integrating sphere, reproducibility few %), prototype tests (light monitoring and recovery, temperature controlled frame, energy resolution), fADC-based readout and triggering

• Discussion about crystal selection and testing sequence at different institutions

• Select a sample from 10+5 (2014) and from 30 (2015) crystals, then test at one institution, and send sample to the next institution

• Discussion about using PbWO4 crystals at an EIC

• Action item: GEMC of crystal matrix in EIC detector environment

CRYSTALS AT THE DIFFERENT INSTITUTIONS

• IPN-Orsay has BTCP crystals for testing optical and irradiation setup. Ordered 3 CRYTUR crystals and expecting them in January 2016

• CUA has BTCP crystals for testing optical and irradiation setup. Also has one 10-cm long CRYTUR crystal (from Rainer) and one 2x2x2 PbF2 cube from SICCAS (through VSL)

• JLab has 11 SICCAS crystals from 2014 (9 are installed in the prototype, #1 and #4 are available for testing). Also has 30 SICCAS crystals from 2015, which have not yet been tested

• Caltech has 2 crystals from the SICCAS 2014 set (#5 and #11). Plans to do proton irradiation tests at Los Alamos with crystal #11 over next few months

• BNL has 2 crystals from the SICCAS 2014 set (#7 and #15). Plans to have these crystals tested at Caltech before returning

CRYSTAL TEST PLAN

• Select subset of crystals from both 2014 and 2015 by next NPS meeting (December 2015)

• Send crystals to one facility for testing

• Once tests are done send crystals to the next facility. Need to check on logistics for sending crystals to Europe.

CRYSTALS AND EIC

• Discussion about using PbWO4 crystals for the EIC endcap calorimeter and reconfiguring the NPS for that purpose

• Action item: GEMC of crystal matrix (~1000 crystals of dimensions 2x2x20 cm^3) in EIC detector environment

NPS MAGNET

• Discussion about two possible options for NPS magnet steel: parts of existing magnets, e.g., 45D45, or parts from the SBS counterweight

• Additional steel for WACS experiments could be procured through UK funds

• 3D magnet model has been sent to the designer

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

• General agenda topics as discussed previously include:

• 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:

• Background simulations

• Plan for crystal testing 2015/16+

• Update on magnet

• Readout

• NPS collaboration meeting planning

• Other...

NEXT MEETING: THUR 10 DECEMBER, TIME: 9:00 AM (EST)