General Meeting Summary 3/23/17

MAGNET

• Main coil, yoke, and corrector coil have been ordered

• Discussion about a few details of yoke steel cuts and main coil fixed radii

• Action items:

• Fringe field mitigation
• Magnet mapping - create an outline of where to map and how to do it

INFRASTRUCTURE

• Semi-clean room being setup for PbWO4 crystals at JLab (along with one for GEMS) - tentatively ready April/May

• Magnet assembly space would be in front of these rooms - action item: check if there are special needs for water/power etc.

CRYSTALS

• Procurement for 460 crystals has been submitted (also on order are 320 PMTs) - the first 100 crystals are anticipated to arrive around June

• Discussion about quality assurance test plan draft

• Action item: finalize the draft and circulate - include information on what the company will provide and initial inspection (visual for cracks, transparency), dimensions, and labeling

PMT HIGH VOLTAGE DIVIDER TEST RESULTS

• R4125 active (rectangular) divider was tested with two light sources (fast solid state laser, LED)
• Results are shown as normalized amplitude vs. repetition rate

• laser: signal drops by 20% from 10^3 to 10^5 Hz, then increases. This may be due to the scintillation mechanism being slow relative to the laser.
• LED: used LEDs of different intensities to adjust the voltage of the signal

• Conclusion: divider works with good linearity up to 1-2 MHz consistent with design specifications

• Another test was done to check the sensitivity of the signal to the PMT HV: different HV settings at fixed intensity. Note that the divider is powered from the anode current, so changing the PMT HV also affects it. Result: good linearity up to 1-2 MHz.

• Discussion about next steps

• Compare performance with cabling and fADC (short and longer/60ft cables)
• Action item: decide if we should move to production of the rectangular design or consider the divider part of a global cabling plan, which may favor a circular design
• Provide drawing with detailed description of production divider

NEW PHYSICS

• Meeting scheduled for 28 March with JLab management, NPS representative and proponents of WACS and KLong proposals

• TCS proposal: decision on whether or not it will go forward depends on preliminary projections - results should be available in next few weeks

NEXT MEETING: THUR 13 APRIL at 9:00 AM (EDT)