1. Scrubbing Run: TDI, MKI and MKE interlocks Chiara Bracco, Jan Uythoven ABT/BTP Acknowledgments: T. Baer, M. Barnes, E. Carlier

2. 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

3. Additional Slide

4. 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.