MICE/ISIS Joint Operations 2 - MICE Muon Beam Update (post- meeting)¶

The MICE Muon Beam has been running for 6+ years. Since the last meeting it has been exercised a number of times in preparation for the upcoming weekend runs.

The FuG power supply has been installed and is normally left on at 200 A when the Decay Solenoid is not in use.

One issue was the failure of a control board in one of the Danfysik 855 supplies: although MICE had a spare board, the whole box of spares could not readily be found as everything had been moved during the R9 building work. Need better labelling and tracking of such. (I still need to find the spare Danfysik 9000!)

The intent is to run during the day at weekends, leaving the equipment in a MICE-defined "standby" state over the Saturday night - similar arrangements will likely re-occur in Step IV proper. During "running" there will be MICE in the MLCR who should catch problems and contact BLOC (or similar) to escalate to expert if needed. ISIS only likely to encounter and need to react themselves to problems during "standby". In general, action (by either MICE or ISIS) should be to make safe and await expert investigation, as opposed to making an emergency repair.

Mostly this should be obvious - e.g. magnet power supplies have a big emergency off button on the front.

There was discussion (anticipating next week's MICE-ISIS Safety Management mtg) about the MICE Target in standby mode: it will be left levitating with the frame raised. The MTENABL Castell key will be with ISIS - this both prevents the target frame lowering (preventing possibility of physical interference with ISIS beam by dropped target) and ignores the target state (preventing ISIS trips due to glitches in the MICE electronics). Implications though are:

• The target mechanism remains electrically live (60-120 V d.c.). There is a "Target On" warning beacon on the target assembly in this state. In the event that ISIS need emergency access to that specific part of sector 7 - end of dipole to ion pump - they should ask the MOM to get the BLOC in to power off the target. The ideal is to have the BLOC within 30 mins, compared with ~ 1 hour to get Health Physics permission to access that area anyway.

• We need to know what the implications are for powering off the "vac-rack" (in the ISIS RF Hall); e.g. any ISIS dependency on Gate Valve state signal.

• Dependencies on services, i.e. water and compressed air.

Expected ISIS staff interventions¶

Italics denote an emergency response action, the rest are by advance request from BLOC/Beamline Coordinator.

• Target
  • Raise target frame by hand if failed
  • Power off vac-rack in emergency (e.g. a power supply emitting smoke)
  • Check target vacuum, and open/close gate valve as needed
  • (Compressed air)

• Conventional magnets
  • Crash-off a PSU
  • turn off water if leak
  • Maintain power supply (change board)
  • Swap beamline polarity
  • Beampipe vacuum/pump support
  • (MICE water)

• Decay Solenoid
  • Fast shutdown of the PSU
  • Emergency shutdown of the Linde fridge
  • Possible troubleshooting of the FuG supply?
  • (MICE Hall aircon)
  • (Compressed air)

• Proton Absorbers
  • (Compressed air)

• Beamstop
  • None