General Meeting Summary 4/5/18

PROTOTYPE AND SIMULATION (Vladimir, Alex Somov)

• Discussion of prototype cosmic data analysis result vs. simulation of the prototype setup - globally looks good

• Action Items:

• Remove LY source comparison as setup is different and cannot directly compare with prototype
• Add assumptions that went into simulation
• Add conditions for prototype measurement

• Discussion of prototype calibration studies

• Demonstrates calibration procedure
• Energy resolution on order 2.1% (ideal would be 1.3-1.4%) - currently limited by setup to improve resolution

Action Items:

• Test different high voltages - at low voltages particularly susceptible to magnetic fields
• Check if possible to remove additional material (TRD, GEM etc.) to reduce scattering

• COMCAL as prototype - design is flexible to accommodate a carbon structure to hold crystals

PMT DIAMETER MEASUREMENT (Vladimir, Hamlet)

• Measurement of 20 PMTs were performed by Hamlet

• Result is 18.86 +- 0.066 mm (systematic error is 25um)

• This tolerance is 10x smaller than that quoted by the manufacturer (18.6 +- 0.7 mm)

• Action Item: measure another 20 PMTs

CRYSTALS (Vladimir, Rong Wang, Ho San, Tanja, Carlos)

• Visual inspection of 40 crystals from SICCAS shipment 3 shows the most of these are not passing requirement due to old labels traces, yellow coloring, significant cracks and bubbles in bulk and on surface

• Ongoing work at IPNO on cross calibrating the crystal testing setups - now have a much better understanding, results will be shown at a future meeting

• Discussions with CRYTUR ongoing - there has been a delay with obtaining the required crucibles for making crystals to NPS specifications, but the company expects to start first tests in the second part of April

NPS FRAME (Carlos)

• Ongoing work: handling cables in back

• Discussion about frame simulation spectra with different gap widths.

• Previous studies have shown that up to 1mm gaps are reasonable and tail contribution not a concern
• For larger gaps contribution of tail can be significant
• Might be good to quote FWHM instead of RMS

MAGNET (Bogdan)

• Assembly and testing to start in April

TCS BACKGROUND STUDIES (Vardan)

• Discussion of simulation results

• Current used is standard CPS current of 2.5uA electron beam

• Based on rates simulation may need to exclude central region of tracker - this cutout propagates to more backward detectors

• Marie's studies suggest that removing this region does not affect the physics

• Discussion about electron/positron energy spectrum and why no electrons above 2 GeV - seems to be due to finite angular acceptance, but might require further study

TCS Uncertainties (Marie)

• Discussion of current results - need to iterate with Vardan's recent studies

NEXT MEETING: THURSDAY 26 APRIL AT 9:00AM (EDT)