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** Carlos - [[Media:High current polarized gun for positrons - slides for April 6 2022 meeting.pptx]] == Upcoming events... ==

...this outline for a new scheme to readout the delayed helicity for Physics Events Trigger (instead of using Scalers RingBuffer): # Report current seed value

** Carlos' e-gun proposal slides [[media:DRAFT 2 Slides for Joe on the high current polarized HV gun plans.pptx]] == Upcoming events... ==

# Measure neutron events in chamber. Neutron radiation detectors in injector region will indicate if # Measure rate vs beam current (0.01, 0.1 and 1.0 µA)

...s Carlos' ERL09 presentation about similar observations while running high current in the FEL gun: [[Media:FEL-Photocathode-'arcing'-ERL09.pdf]] ...cern.ch/accelconf/ERL2013/talks/wg103_talk.pdf Bruce Dunham's talk on high current cathode damage]

...tried to reach 1 mA (300kV) stable running, but the gun HVPS trips off on current a few minutes later, max time is about 30 minutes, see link here: [https:// ...did not seem to help much. What it seemed to help is to increase the beam current SLOWLY.

...edia:Hel_8218_0.txt]] shows that S1 helicity is lacking FADC by 0 to a few events. FADC helicity is correct because it is read event by event in the same mod :* Mott Mott_Sample 8314, (FADC+TDC+Scalers), beam current = 0.9 uA.

# Measure neutron events in chamber. Neutron radiation detectors in injector region will indicate if # Current scan: 0.5 uA for 1 hour, 0.25 uA for 2 hours

In the meantime, the Run 1 wiki has been updated run a chronology of events/logbook entries and the final on-line spreadsheet of runs and on-line resul : Beam current

* To run large statistics run (using LUMI events): * The current geometry for the Bubble Chamber is in gemc and is shown below:

- Electron Dump: isolated to measure beam current, 2 kW dump. Make sure no neutrons are produced in the ceramic insulator - Discriminate between (γ,α) and (γ,n) events using the acoustic signal. The acoustic signal may help to

#'''Measure asymmetry vs. dead-time and beam current [[Media:Deadtime_spreadsheet.ods]]''' #Determine number of events needed for IHWP=IN and OUT