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P2 events & perturbations

P2 events & perturbations. Overview. 02.08 : Beam interlock 07.08 : P2 18kV filter trip 08.08 : Perturbation PX24 cooling water 22.08 : Magnet trip. 02.08 : Beam interlock. LHC beam was dumped twice (12:36 and 16:30 ) due to an interlock from the PX24 access system Cause :

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P2 events & perturbations

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  1. P2 events & perturbations ALICE Technical Coordination Meeting

  2. Overview ALICE Technical Coordination Meeting 02.08 : Beam interlock 07.08 : P2 18kV filter trip 08.08 : Perturbation PX24 cooling water 22.08 : Magnet trip

  3. 02.08 : Beam interlock ALICE Technical Coordination Meeting LHC beam was dumped twice (12:36 and 16:30) due to an interlock from the PX24 access system • Cause: • Water leaking from the SX2 roof infiltrated in the access system for PX24, triggering the access interlock • Impact for ALICE: • None (other than stop of beams) • Remarks: • The access interlock causes an emergency beam dump • Actions: • Emergency repair of roof • Longer term: assessment of status of roof

  4. 07.08 : P2 18kV filter trip ALICE Technical Coordination Meeting • Cause: • Problem on protection relay (identical to trip on 25.07) • Impact for ALICE: • Trip caused no perturbation • Switching on the filter (at 09:16) caused several perturbations • Again, mainly CAEN equipment is affected • Remarks: • Dipole and Solenoid were preventively ramped down before turn on of filter • As on 25.07, DAQ and HLT were left on (are usually switched off, SL gave green light without switching off) • Actions: • EL changed the suspect relay • Still to be decided: ALICE strategy at switch-on of this filter

  5. 08.08 : Perturbation PX24 cooling water ALICE Technical Coordination Meeting • As from ~9:00 perturbations on the cooling water temperature are observed • Mixed water, cooling the racks in CRs • Short (10 mins.) ‘spikes’ (2-3 degrees) in temperatures

  6. 08.08 : Perturbation PX24 cooling water ALICE Technical Coordination Meeting • Cause: • Failing servomotor on regulation valve in mixed water circuit • Impact for ALICE: • Virtually no effect on cooling efficiency • Remarks: • None • Actions: • CV changed servomotor on 11.08

  7. 22.08 : Magnet trip ALICE Technical Coordination Meeting • Cause: • Power glitch (06:51) tripped Dipole • Impact for ALICE: • None (no physics) at time of trip • Operator error in CCC tripped Solenoid when intending to ramp up Dipole • Remarks: • Also on other occasions (normal ramp for access), bad communication between CCC and ACR caused some confusion • Actions: • Again, remind the procedure with CCC and shift leaders • Longer term: implement software handshake

  8. ALICE Technical Coordination Meeting

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