MPS Minutes 20210825

Present: MA, HH, RN, AD, MR, KL, AL

Commissioning status

• Finished scans in medium energy section
• Initial issues with EMBT:MB0 power supply stopped us from taking scan the week before
• Taking scans at EINJ setpoint 950 - 975 ~10.5 MeV
  • Higher EINJ setting increased dark current by factor of ~3. Spill levels in medium section ~factor of 2-3 higher compared to 2020 data. In high energy section as well.
  • Still need to take dark current scan to add background to thresholds
  • Should also have a study of energy dependence and dark current
• 10kW was reached at 25MeV (EINJ setting ~710). No issue with BLMs tripping
• Problem really mostly with tuning procedure when beam is on view screens
  • Is there a way one could implement interlock procedure that disables a particular detector when specific view screen is inserted and re-enables when the view screen is out of the beamline again?
  • Presently, we're tripping when on view screens as beam is spilled and trip settings are for well-focused beam.
  • We shouldn't sacrifice safety for convenience and just bump up thresholds
  • Rod: This requires well specified changes
  • Rod: Option for more detectors to discriminate between de-focused and focused spills? Might be to complicated for immediate solution.
  • Threshold settings depending on mode of operation? Need to discuss with Thomas.

E-LINAC status

• 10kW was reached at 25MeV (EINJ setting ~710).
• Next goal is 10kW at 30MeV.
• Fields were measured by RPG outside of the ehall and didn't appear to increase with higher power
• RPG measured fields at the dump afterwards. ~10uSvr/hr as usual.
• On Wednesday evening energy was already increased to 27.8 MeV at 6kW. Tune wasn't ideal. Spills just at threshold limits in high energy section. AL slightly increased levels from 50nC to ~75nC to avoid trips. In high energy section we have factor of 2 safety margin before hitting 100nC in 100ms losses.

AOB

• AL reached out to Thomas about meeting for global reset. Will arrange meeting time when Thomas is back from vacation
• After MPS re-commissioning report, AL will write up LED calibration specs
• Still need to get Post-Mortem data to analyse from BLM trips.
• No update on fibre. Reflector has not arrived yet.