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Scrubbing Run: TDI, MKI and MKE interlocks Chiara Bracco, Jan Uythoven. ABT/BTP Acknowledgments: T. Baer, M . Barnes, E. Carlier. Scrubbing Run with 25 ns beam 4/10-8/10. Scrubbing run: Injection and accumulation of trains of 144-288 bunches Long periods without injections
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Scrubbing Run: TDI, MKI and MKE interlocksChiara Bracco, Jan Uythoven ABT/BTP Acknowledgments: T. Baer, M. Barnes, E. Carlier
Scrubbing Run with 25 ns beam 4/10-8/10 • Scrubbing run: • Injection and accumulation of trains of 144-288 bunches • Long periods without injections • The TDI has to be retracted to parking position if vacuum worse than given threshold • Proposal to be confirmed:1E-7 in IP2 and 1E-8 in IP8 • Announcer advising when limit exceeded? • Make special scrubbing sequence for topping up. Put MKI in STANDBY before moving out the TDI Risk of MKI erratics with TDI retracted ? TDI interlocks: injection inhibit if TDI jaws open to parking (injection BIS) no beam permit inhibit to charge the MKI PFN and no pre-pulse trigger no erratics In case the MKI PFN gets charged and then the TDI moved out before pulsing:MKI interlocks : “NO-TRIGGER PULSE” the PFN gets discharged through the dump switch ~2.5 ms after the injection pre-pulse Risk of extraction from SPS with TDI retracted ? TDI interlocks: SPS extraction inhibit if TDI jaws open to parking (injection BIS) no beam permit inhibit to charge the MKE PFN and no pre-pulse trigger no erratics In case the MKE PFN gets charged and then the TDI moved out before pulsing (15 ms window!): MKE interlocks: “NO-TRIGGER PULSE”. • MKE4 will be discharged by clipper switch. • No clipper switch in point 6 resulting in minutes to discharge, however: • MKE6 running at half nominal voltage, unlikely to perform erratic • TDI will only have moved by few microns in those 15 ms
UFO Proposal during scrubbing (Tobias) • If vacuum pressure at TDI below following limits: Move in TDI. • Limit for TDI B1: 1e-7 mbar at VGPB.231.4L2.X (tbc) • Limit for TDI B2: 1e-8 mbar at VGPB.231.4R8.C (tbc) • If MKI vacuum pressure below SIS injection interlock: • Disable SPS MKE in order to avoid beam extraction. • Load timing table: INJECTION_BI_MD, Switch to BLM Study Buffer • Enable MKI. • Request via the LHC injection sequencer the next nominal injection. • Beam will be accelerated but not extracted from the SPS (dump on SPS internal dump at end of cycle) • MKIs will pulse at gap for next nominal injection. • Repeat above about 10 times. • Load timing table: INJECTION_BI, switch to IQC Buffer • Enable SPS MKE for nominal injection. • Do nominal injection. • If MKI vacuum pressure below SIS injection interlock: • Disable SPS MKE in order to avoid beam extraction. • Load timing table: INJECTION_BI_MD, Switch to BLM Study Buffer. • Request via the LHC injection sequencer the next nominal injection. • Repeat above about 10 times. • Put MKI to standby. • Retract TDI.