R.Giachino / M.Albert Be/op 30 th March 2015 LHC Machine check out 1v1

Training quenches S45 on target after 50 ramps! S34 is just below the target…

Quench campaign in S45 ● Very good availability of the cryogenics over the 2 weeks!!!

Status of the powering tests Successfully executed; to be signed by MP3 PGC on-going Trips of the last days: -RQD/F.A45 – trip from flattop= training quench -RSD2.A67B2 – 0V crossing; if it happens again, ramp rate could be reduced or MP3 has to discuss the possibility of increasing the threshold -RCD/Os in S78 and 45 – normal training when powered together; now completed everywhere except S34 -RQT13.R1B1 – spurious trip? -RQ6.L1 – high difference between the reference and the real current when squeezing; now corrected -RQD.A81 quenched during ramp-down (15.L1) => checked by MP3, OK to continue

powering groups of circuits

Week end plan Preparation for RB.A34 earth fault test. Intervention in point 4 has priority Intervention in point 12 Continue training quenches on RB.A45 Full Operational machine cycle tests BIS interlock reconnection Nominal sequence tests Precycle, ramp and squeeze in all possible sectors RF tests Collimator tests LHC and experiments mostly closed during week end 6

Investigation on RB.A34 fault to ground ● Friday – Xray taken from the top. – The power part of the system to burn the debris was working correctly. – The DAQ electronics to be finalized. Rescheduled not before Monday S34 at 3.2 K

Interlock Loop & LBDS BIS LOOP reconnect normal configuration to be complete PIC-BIS Few circuits left to be tested Safe Machine Parameter in progress BETS at 450 GeV and 6.5 TeV RB 45 nominal. To be repeated when RB 78 available

RQF S12 intervention ● RQF S12 ELQA performed on Thursday-Friday – Nothing found – Friday evening re-qualifying RQF/QRD circuits – Saturday 12:36 QF tripped at Flat Top – Piquet called IN due to earth fault – Intervention to check the power converter – The fault was not in the power converter – Sunday morning we did a visual inspection 9

QF S12 intervention ● RQF S12 ELQA performed on Thursday-Friday – Nothing found – Friday evening ri-qualifing circuits – Saturday 12:36 QF tripped at Flat Top – Piquet call IN Due to earth fault present – Intervention to check the power Converter – The location of the Fault not in the Power converter – Sunday morning we did a visual inspection 10

RB.A78 Trip Saturday 17: RB.A78 tripped while going to standby. signal I_EARTH_PCNT = -109% disappeared after. Reset power converter ok >> Cycled up to 2000 A few times. MP3 suggesting ELQA measurement today. RB.A78 nQPS: Voltage feelers (2)

Operation tests Nominal sequence : Some Machine Critical SETTINGS checks still failing for LBDS. ABT informed. HW/database mismatch for ABORTGAP CLEAN parameters BPM calibration failed : host not reachable >> BI informed BLM MCS checks BLM sanity check and MCS ok now for 7/8

Beam Instrumentation BLM system operational BLM BIS user permit should be enabled BLM team need more tests. Wirescanners Operational

Collimators ● System that is operated through functions, synchronously with converters and RF, in ramp and squeeze. ● - Machine protection tests – completed for ring collimators ● Checked individual "discrete" interlocks for – 18 position/gap interlocks per collimator (~1800) – - ~600 temperature sensors ● OP sequence: – collimators tasks are completed – ready for the first commissioning! ● - Missing: interlock tests with final distribution of energy/beta* ● - Issue in running the TCDQ through cycle -> ATB informed ● - Injection protection: MP tests still ongoing critical settings were changes last week!

Ramp and squeeze, precycle ● Extensive tests of ramp and squeeze, but mostly in small bits (always few sectors missing). ● RQ6 trips in 1 and 5 during squeeze to 40 cm fixed. The power converters were asked to ramp down too quickly. – Squeeze length increased by 90 seconds (from 414 to 504 seconds). 15

Ramp and squeeze, precycle ● Precycles tested in all available sectors. Working rather well now with the tricks to reduce the duration. 16

Sunday – cycling & PGCs RAMP & SQUEEZE on S23, S56, S67 and S81 RQD.A45 tripped while going to STANDBY (fault: VS_RUN_TO) PGC1.3 on ARC45 failed due to several 600A circuits tripping before reaching FT (RQTD.A45B2 quench was first) RQD.A81 quenched during ramp-down (15.L1) => checked by MP3, OK to continue RQ6.L7B1 tripped during ramp down on 0V-crossing

Access requests WHOWHEREWHENWHATDuration BISIR3 & 4Back to nominal3 hrs. BISUa63& 67Bis team2 hrs EN/MMEPoint 4Xray Material2 hrs. EN/ELPoint 2Earth Fault2 hrs. ELQAPoint 8RB 78 MPEPoint 4Earth fault intervention

Plan of the day RB.A34 earth fault investigation-intervention has priority Intervention RQF 12 Possible visual inspection >> ELQA investigation RB 78? Continue PGC’s S45 Full Operational machine cycle tests BIS interlock reconnection continue Nominal sequence tests Precycle, ramp and squeeze in all possible sectors RF tests Collimator tests LHC & Experiments closed after access 19

BLM BLM sanity check failed (problem in P2)

PIC – BIS tests M. Zerlauth finished tests on following circuits: RQ5.L/R5 RQ9.L/R5 RQX.L/R5 ARC45 couldn’t be done due to unavailability of P4

remaining HWC tests PGC1.3 on ARC45: trip of RQTD.A45B2 (quench at 547A) before reaching FT => to be repeated

Investigation on RB.A34 fault to ground ● Precise fault localization through electrical measurements performed in the tunnel by ElQA team (including reflectometry) ● X-ray imaging try to localize precisely the fault to ground. ● Many Lab tests to simulate the behaviour of the fault to ground in a configuration as close as possible to the one of the tunnel ● Several possible solutions investigated and risk analysis assessed – Cryogenic investigation to try a local displacement – Local heating of the diode via injection of small current – Local (global) warm-up – Injection appropriate current through the fault to try moving/eliminating it. C19L4 voltage to ground is flat

Event of RB.A34 ● During the 13 th training quench of RB.A34, after the few secondary quenches, and during the ramp-down, additional “spurious” quenches were observed Voltage across magnet diodes ~90 s RB current 2300 A 800 A C19L4

Ground fault, fuse gone (1A or 100mA?) ~17:57 No fault anymore? Or next fuse? RB.A78 I_MEAS and I_EARTH_PCNT

RB.A78 nQPS DS: U_DIODE signals

RB.A78 nQPS: Voltage feelers (1)

RB.A78 nQPS: Voltage feelers (2)

Resolution : < 0.5 mm

From a closed interconnection, best angles to radiography the half moon of the diodes Axe1 Axe2

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Sunday – MP tests of collimators Test of energy gap interlock during collimator functions: Interlock when energy threshold reached :  MDC and PRS continue moving:  Test of beta-star gap interlock during collimator functions: Interlock when energy threshold reached:  MDC and PRS continue moving: 

RB.A78 nQPS: Voltage feelers (3)

BIS: from now to nominal situation ● BIS system: – Most clients disconnected – Sector tests configuration (HW jumper) – LBDS disconnected. – Beam startup: – All clients connected to the loop. – Strategy is to connect remaining inputs when possible. ● Condition to close the BIS LOOP in nominal condition: – LHC access Key on Beam mode – LHC Vacuum valves open – Hardware commissioning finished; all circuits ON and no faults – No interlock from non maskable clients. 42

Remaining issues Vacuum valve MSI-TI2 (VVGS.29528) interlock SPS EXT1 master BIC to be tested extraction conditions established >> Markus - BIC LHC probe beam re-phasing issues, stability issues => often BQM interlocks Threshold increased, to be checked with beam >> Giulia BTVDD image orientation > on hold until LBDS experts decide on preference BI-ABT decision to be made >> Jan -BI Controls: CMW/RDA issue affecting several clients new libraries released CIBDS problem while arming LBDS > Bruno, ongoing LBDS-XPOC: Missing BI data: (BCTFR, BSRA, etc..) >> Nicolas M- BI

Remaining Test LBDS with LOOP closed: Arming sequence Circulate and dump TCDQ ramp

LBDS and Kickers LBDS – Full check-out tests needed with system fully connected: – Energy tracking tests up to 6.5 TeV; – Arming the system connected to BIS once beam permits are OK – Circulate and dump sequence. – Machine protection tests with loop closed. 45

Saturday - collimators Test of collimator sequences TCDQ B1 / B2 PROFILE_OUT_OF_ENERGY ERROR position is within limits but error cannot be reset “PRSStatus” FAULTY - unable to reset it Ramp & SQUEEZE of collimators – movement + sequences OK Energy limit: 45mm Collimator position: 15mm

PC’s issues RQF.A12. Thursday ELQA done nothing found. Circuits re-qualified Trip at Flat Top no quench Earth fault EPC Piquet Intervention Nothing found on the converter side. Fault still there RQD.A45 and RQF.A45 Tripped a few minutes after flattop >> Reset OK RSD2.A67B1 RSD1.A67B1 RSF2.A67B1 tripped at end of ramp down RB.A78 tripped while going to standby from FT Earth Fault disappeared after 15 mins. RCO/RCD.A78B1 trip at the end of the ramp!!! 5 th time Three quenches in a shift.... Fully trained OK

PC’s issues RQF.A12. ELQA done nothing found. Trip at nominal no quench Earth fault >> EPC Piquet Intervention Nothing found on the converter side.

PC’s issues PC’s issues: RB.A78 tripped while going to standby from FT Earth Fault disappeared after 15 mins. Standard procedure in case of an earth fault is to perform HV qualification by ELQA. From the voltage feelers it seems that the earth fault is in the warm part so I would suggest that ELQA goes in on monday. Also better to first perform some simulations (Emmanuele, Monday) before we power the circuit again. Arjan

Investigation on RB.A34 fault to ground ● Investigation continued ● Summary: – the power part of the system to burn the debris is working correctly, – the DAQ electronics is working correctly, but only at low range the capacitor bank charging voltages, – for high charging voltages the recorded signals are “unphysical” and not easy to interpret. Rescheduled not before Monday

Week-end plan Preparation for RB.A34 earth fault test >> Monday Priority to PGC’s RB.A45 and all the remaining circuits. Full Operational machine cycle tests BIS interlock tests Nominal sequence tests Precycle, ramp and squeeze in all possible sectors RF tests Collimator tests LHC and experiments “mostly” closed during week end

Operational cyle Nominal sequence : signature missing for CHECK MKD MCS SETTINGS SET BETS READTABLES TRUE failed: ABT is working on it HW/database mismatch for ABORTGAP CLEAN parameters BPM calibration failed : host not reachable >>BI informed BCT OFFSET correction failed because system B not OK DC BCT calibration finished. Overall result: SUCCESS BLM MCS checks failing for2 card only BLM sanity check and MCS ok now Issue when loading the TCDQ B2 Injection Protection collimators: machine protection tests on-going

Beam Instrumentation BLM system operational BLM BIS user permit should be enabled BLM MCS and SANITY CHECKS finished BLM team need more tests. New thresholds and monitor factor uploaded tests ongoing Wirescanners Operational BI/OP tests RBAC problem for BCT, BLM Tasks updating with the 2 new crates (Laurette), BPM calibration failed “device not accessible” RING DC-BCT calibration task not working >> Done

S 12 QF.A12 trip (Wednesday)

Wednesday S 12 QF.A12 trip (Saturday)

Remaining issues Vacuum valve MSI-TI2 (VVGS.29528) interlock SPS EXT1 master BIC to be tested extraction conditions established >> Markus - BIC LHC probe beam re-phasing issues, stability issues => often BQM interlocks Threshold increased, to be checked with beam BTVDD image orientation > on hold until LBDS experts decide on preference BI-ABT decision to be made >> Jan -BI Controls: CMW/RDA issue affecting several clients new libraries released CIBDS problem while arming LBDS > Bruno, ongoing LBDS-XPOC: Missing BI data: (BCTFR, BSRA, etc..) >> Nicolas M- BI

Test to be done BIS LOOP closed ● Vacuum valves test with BIS loop closed ● LBDS BETS with 45 finished ● Circulate and Dump