Thursday, May 21, 2015, 11:00am EDT - Compton

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Agenda

Meeting room=F227 in Cebaf Center

General

• Update on test at 2 pass (Gaskell) pdf

DAQ

• Lots of DAQ work planned for this summer (Bob - if available)
  • Remove old Saclay counting DAQ
  • Put in new photon counting DAQ
  • How will this impact electron detector?
  • VETROC tests

Electron detector

• Updates from Alexandre - did we learn anything from the little bit of beam we took?
  • Cannot get closer than 22 mm
  • Run 1370 : 1857 triple coincidence ABD, 1634 no hit plane C, 223 hits plane C at thresold 21 : 12 % efficiency though cannot conclude since it could be photons and corellated noise
  • https://hallaweb.jlab.org/dvcslog/compton/366
• Updates from Manitoba

Photon Detector

• Analyzer - would be nice if we could get background subtracted asymmetries from 2 pass data.
  • Bob has put the analyzer on GitHub: https://github.com/rwmichaels/compton
• Plans for upgrades or improvements this summer?

Laser

• Primary goal is implementing polarization setting and monitoring a la Hall C.
  • Work plan: Compton elog 365
  • Controls modifications request: pdf
• Other tasks: Gather spares, get laser lab fully functional

Minutes

• Dave should get the Bluejeans stuff working properly - this will make life easier for future meetings.
• Dave went over 2 pass commissioning stuff - a lot of things went well!
• Electron detector commissioning trickier - at "22 mm"from beam , Alex starting seeing more rate in photon detector, ion chambers tripped. Info from BPM between dipoles 3-4 suggests beam might have been at larger y than expected.
  • 2 example spectra shown - not clear if we're seeing "real" signal or not. Might be coming from photons. No clear Compton events.
  • Plans for summer include removing detector to inspect, get DAQ working better. Try with QWADs?
• Manitoba making progress on electron detector - but it takes time getting all the parts, connectors etc. Mitra has some questions about QWADs - will talk to Dipangkar offline.
• Photon Detector
  • Gregg notes that working on the Analyzer is a plan for the summer. Also thinks we might need something for simple online monitoring since old DAQ is going away.
  • Detector work (Brian): Add temperature monitoring to detector. Would like to do more linearity measurements at CMU - Dave will check on whether the old loan agreement is still in force.
• Alexandre will submit proposal to EIC R&D - focus on vacuum chamber adapter that would allow putting Hall C detector in Hall A and vice versa (?).
• Dave notes that Elke Aschenauer suggested a meeting of BNL and JLab polarimetry experts to discuss strategy at an EIC.