SPS crab cavity test stand Results of interlock

SPS crab cavity test stand – Results of interlock test and readiness for taking beam G. Vandoni MPP 18 th May 2018

Outline Test stand layout MD phasing Generalities on interlocks architecture Machine and equipment protection BIS RF Timescales Conclusions G. Vandoni @ SPS & LHC Machine Protection Panel 2

MPP and Doc on crab interlocks for SPS 9 Dec 2016: Foreseen interlocks for the operation of crab cavities in SPS 29 Sep 2017: Final plan for interlocking of crab cavities in SPS EDMS 1843638: Approved! Interlocks for the HL-LHC Crab-cavity test stand in SPS, L. Arnaudon, G. Vandoni R. Calaga, K. Cornelis, T. Otto, D. Wollman, 13/3/2018 EDMS 1921540: DSO tests report, released 8 May 2018 Electron lens review 2016, indico R. Calaga, RF Overview of crab Cavities for HL-LHC and potential failure modes G. Vandoni @ SPS & LHC Machine Protection Panel 3

Test stand architecture – tunnel Cryogenic distribution line RF power transmission lines Crab-cavity cryomodule Y-chamber RF power waveguides CM gate valve SPS vacuum sector valve Moving Transfer table G. Vandoni @ SPS & LHC Machine Protection Panel 4

System architecture – Crab-cavity test stand Helium pumps Vacuum sectorization valve Valvebox 2 Service module RF power, loads & circulators Vacuum sectorization valve Y-chamber Transfer table Cryomodule Trans Y-chamber port l ane

Overview of the MD phases The MDs were split into 4 main categories (for 2018): 1. RF-beam commissioning (2 x 10 h) 2. Transparency (1 -2 x 10 h) 3. Performance (1 -2 x 10 h) 4. High intensity (2 x 10 h) low intensity, 1 to 12 bunches, 2 1010 MPP review high intensity, 1 bunch to 4 x 72 trains Before going to high intensities, a special MPP will be held to assess the cavity performance concerning protection issues. Progressive increase in energy + intensity || failure scenarios: Will perform failure studies in parallel during the MDs, as the beam parameters vary. flexible interlocking as we learn to know the system. Lee Carver, SPS-CC MD Planning Overview, SPS Test Day #2 6

Interlock types type Cryogenic distribution line why what Personnel safety Radiation (X-rays) ODH and cryo hazard mechanical hazard Access versus RF Power to cavities Table movement Machine protection Aperture Beam & extraction versus table position, movement, vacuum sector valves Protection SPS and crabs SIS Protection SPS and crabs RF Power versus Vacuum, cryogenics. Equipment protection Beam versus HOM power G. Vandoni @ SPS & LHC Machine Protection Panel 7

RF Controls layout ACCESS G. Vandoni @ SPS & LHC Machine Protection Panel 8

RF Controls layout To beam interlock BIS board TO/FROM Access ACCESS To RF Power interlock G. Vandoni @ SPS & LHC Machine Protection Panel 9

Services INPUT IOT Interlock modules To Access HOM Power threshold* To CIBUs RF INPUT To RF Power Same for IOT 2 *HOM Power threshold 200 W implemented to protect LHC-type HOM coupler feedthroughs after failure of high power new design HOM FT’s during dressed cavity tests G. Vandoni @ SPS & LHC Machine Protection Panel 10

From crab test stand via CIBU- BIS board entries Cryogenic distribution line SIS Permit: Table OUT/IN VVS CIBU SPS RING CC CIBU BLM CIBU BIS SPS RING – BA 6 U BIS EXTR 1 – BA 6 SPS EXTR 1 CC CIBU M • 1 new entry, unmaskable, from CC • VVS exception for V 1/V 3 • Software permit, maskable, with Table position • CC BLM individual threshold setting, in BLM sector’s CIBU • 1 new entry, unmaskable, from CC G. Vandoni @ SPS & LHC Machine Protection Panel 11

BLM one sector< threshold VVSB_61752 open VVSB_61736 open VVSB_61757 open VVSB_61731 open RF parameters set RF PLC status OK HOM Power < 200 W Table undefined / error / moving Table IN *HOM Power threshold 200 W implemented to protect LHCtype HOM coupler feedthroughs after failure of high power new design HOM FT’s during dressed cavity tests Table OUT SPS Ring and Extr CC CIBUs (unmaskable) Beam enabled EXTR enabled Beam NOT enabled EXTR NOT enabled G. Vandoni @ SPS & LHC Machine Protection Panel 12

BIS – Conformity and Functional Tests BIS conformity reports BIS functional tests with time stamping TE/MPE is looking into the time-stamping during table movement tests 2/5 Proposal to go through the procedure with timestamps at the beginning of the MD G. Vandoni @ SPS & LHC Machine Protection Panel 13

RF Power Interlocks IOT REV Circulator REV Load REV Coupler REV IOT FWD Circulator FWD Load FWD Coupler FRW Arc detectors Cryo OK Vacuum - insulation Vacuum - beam Vacuum FPCs (beam) Access Safe All tested or being tested during present commissioning and RF conditioning, off beam RF Power OK 3. 5 10 -7 mbar 4. 0 10 -7 mbar Monitored but not used for interlocking, they may be used for LHC. G. Vandoni @ SPS & LHC Machine Protection Panel 14

RF Power Interlocks - timescales Reaction time Arc detection < 1 ms Reflected RF power (or any RF Power parameter) < 1 ms Vacuum FPC SIS < 0. 1 to 5 ms ≈ 1 s G. Vandoni @ SPS & LHC Machine Protection Panel 15

Interlock non-conformity Table position to Vacuum valves opening is now via software Cable to be pulled for hardware interlock Vacuum to cryogenics is now via software Cable to be pulled for hardware interlock Interlocks Engineering Specification defines Modify the Interlocks Engineering only Safety and Machine Protection Specification to include all equipment interlocks, not the equipment mutual protection interlocks protection G. Vandoni @ SPS & LHC Machine Protection Panel 16

Conclusion • Functional test of BIS with timestamps could be repeated for completeness at MD start • SIS (maskable BIS entry) only includes the table position: it is evolutive Phases 1 -2: READY (after functional BIS test) Stopping point: MPP review in June Phases 3 -4: Evolution of the interlocking scheme via RF parameter set interlocking RF and SIS G. Vandoni @ SPS & LHC Machine Protection Panel 17

Back-up slides G. Vandoni @ SPS & LHC Machine Protection Panel 18

Potential Failure Modes § R. Calaga, Electron Lens review 2016 ELens Review 2016

Truth Table for Transfer Table o TEST STAND ARCHITECTURE ● INTERLOCKS FUNCTIONAL SPECIFICATION o ACTIONS o CONCLUSIONS ACCESS G. Vandoni @ SPS & LHC Machine Protection Panel 20

Aperture and crab cavities NA slow extraction in LSS 6 CCCM LHC beam extraction in LSS 6 Fast extraction to LHC Crab-cavity in beam does not yield enough aperture for extracted beam H. Bartosik @ SPS Test Day, I https: //indico. cern. ch/event/463435/ CCCM aperture Slow extraction of fixed target beam at 400 Ge. V, incl. extraction bump purple : raw beam envelope red: beam envelope + tolerance Crab cavity in beam gives sufficient aperture for slow extraction to NA No bumper dipole interlock (opp. to Coldex) G. Vandoni @ SPS & LHC Machine Protection Panel 21