General Meeting Summary 4/5/18

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  • 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


  • 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


  • 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