Thursday, May 21, 2015, 11:00am EDT - Compton
From Hall A Wiki
*********BLUEJEANS CALL-IN INSTRUCTIONS********* ---------------------------------------------------- 1. Dial Toll-Free Number: 1-888-240-2560 (U.S. & Canada) 2. International participants dial: Toll Number: 1-408-740-7256 3. Enter meeting ID:140287970
Meeting room=F227 in Cebaf Center
- Update on test at 2 pass (Gaskell) pdf
- 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
- 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
- Updates from Manitoba
- 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?
- Primary goal is implementing polarization setting and monitoring a la Hall C.
- Other tasks: Gather spares, get laser lab fully functional
- 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.