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.

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.