Week 31 Summary week 31 02 08 09
- Slides: 35
Week 31 Summary week 31 02. 08. -09. 08. G. Arduini & O. Brüning 8: 30 meeting
Week 31 ● Operation with Multi-bunch Injection since Thursday 29. 07: – 13 fills with up-to 120 nb-1 per fill 109 h of luminosity production ca. one fill per day; peak luminosity: L = 4 1030 cm-2 sec-1 – average fill time of ca. 9 hours (10, 9, 14, 1, 15, 7, 2, 17, 15, 0. 5, 2, 14, 2. 5) – integrated luminosity: 730 nb-1 (40, 60, 8, 100, 60, 20, 120, 90, 8, 23, 95, 25) – ca. 56 nb-1 /fill; average luminosity per fill: L = 1. 7 1030 cm-2 sec-1 ca. 40% efficiency (wrt to scheduled time); total luminosity ca. 1080 nb-1 8: 30 meeting 2
Week 31 8: 30 meeting 3
Week 31 Dump events Fauls & Interventions Monday Tuesday Access system S 23 tripped; SIS fault Pt 2 interlock; Access system Pt 1 Wednesday Thursday Friday EOF; PC trip; EOF; BLM Saturday BLM 3 h Set Up; 3 h 5. 5 h QPS circuit 3 h Set Up; 1 h 3 h Set Up; 3 h 2 h Setup; Access System braker; 2 h. Set Up; 1 h Access System; Access 5 h QPS & BLM Sanity Check; 0. 5 h BLM; FGC and 2. 7 h Beam Quality Access Injectors; Sunday Cryo; QPS Total 10. 5 h QPS & 1. 5 h Cryo; FGC (Access); 1. 5 h Set Up; 2. 5 h Set Up 3 h QPS Time without Beam [h] 6 10. 2 4. 5 6 7 13 6 48. 2 Time ready for beam [h] 18 13. 8 19. 5 18 17 11 18 119. 8 Physics [h] 12 2. 5 13 7 11. 5 3. 5 14. 5 67% 18. 12% 66. 67% 38. 89% 67. 65% 31. 82% 80. 56% 55. 51% 50% 10. 42% 54. 17% 29. 17% 47. 92% 14. 58% 60. 42% 38. 10% Efficiency LHC Ready Efficiency Scheduled time Comments Test ramp with 2 nominal bunches For periods without studies: 8: 30 meeting Time invested for injection setup Test ramp with 2 nominal bunches ca. 63% efficiency relative to available beam time ca. 45% efficiency per scheduled time 4
Monday 2. 8. ● Analysis of the noisy spectra observed at injection and flat-top: – The peaks observed are exact harmonics of 50 Hz extending up to 4 k. Hz – Instrumental? – The noise seems to be lower in the BBQ pick-up for on-demand measurements 8: 30 meeting 5
Tuesday 3. 8. ● Test Ramp for operation optimization with 2 nominal bunches: – Beams lost during squeeze at b* = 7 m ● Goal for test ramp with 2 bunches for operation optimizations: – A: Damper and tune feedback optimization: – Test of the Q feedback with different PC regulation loop to reduce noise ✔ – Transverse feedback tests at injection (0. 5 hours) Not yet done – Hump investigations (~1. 5 hours) Not yet done – B: Ramp and squeeze optimization: – Incorporate Q and Orbit FB feed forward into ramp. ✔ – Establish better end-squeeze to collision sequence/settings. Not yet done – Clean orbit in stable beams (ALICE H plane, . . ). Not yet done – Check TCTs. Not yet done – Collimator loss maps. Not yet done – Beam dump validation (Dump with RF OFF) Not yet done 8: 30 meeting 6
Wednesday 4. 8. ● Tuesday to Wednesday night: – Physics fill with 25 nominal bunches with inverted sign of tune split; – Problems related to losses during over-injection into LHC – Initial peak luminosity of 2. 8 1030 cm-2 sec-1; fill lost due to patrol box in IR 1 ● Wednesday morning: optimization of losses during injection: – Single bunch has very good trajectory and no losses in the TL. – Over-injection with 4 bunches leads to losses that dump the beam trajectory changes by ca. 0. 2 mm over all cases (1 to 4 bunch injection); trimmed SPS RF frequency (10 Hz); Decided to correct trajectory in both lines back to reference using upstream correctors (0. 6 mm rms) (origin of change not understood? ). Revalidation of TCDI settings. – Change of some BLM thresholds; 8: 30 meeting 7
Tuesday 3. 8. ● Beam intensities over fill– Losses for Beam 2 higher than for Beam 1 after inverted sign of tune split 8: 30 meeting 8
Wednesday 4. 8. ● Afternoon: Preparation of new physics fill: Physics fill with 25 nominal bunches; No tune split between Beam 1 and Beam 2 15: 45: Starting ramp: e 1 nx = 2 mm; e 1 ny = 3 mm; e 2 nx = 2. 7 mm; e 2 ny = 5. 3 mm; 17: 00: Starting Squeeze; 17: 40: Stable Beams; Initial peak luminosity of 3. 0 1030 cm-2 sec-1; Beam lifetimes of 5 h going above 25 hours after few minutes and rising to 125 h after a couple of hours. – 19: 30: Roman Pots at 25 sigma; – – 8: 30 meeting 9
Wednesday-Thursday 4 -5. 8. ● End of physics at ~11: 00 after 18. 5 hours ~120 nb-1 8: 30 meeting
Thursday 5. 8. ● Go to adjust mode for end of coast study ● Swap H/V tunes for B 2 (crossing coupling resonance) in order to investigate the feasibility of working point with similar to RHIC in collision. Damper can stand the tune swap but not completely transparent (dip in lifetime and tiny losses) 8: 30 meeting
Thursday 5. 8. ● Afternoon: Second attempt for a test fill for ramp and squeeze optimization – (2 on 2 bunches) ● 20: 00 RQ 10. B 2 power converter trip (water fault again) Beam dump – Incorporate Q and Orbit FB feed forward into ramp. ✔ – Establish better end-squeeze to collision sequence/settings. ✔ – Clean orbit in stable beams (ALICE H plane, . . ). ✔ – Check TCTs. Not yet done – Collimator loss maps. Not yet done – Beam dump validation (Dump with RF OFF) Not yet done 8: 30 meeting
Thursday 5. 8. ● New beam process for collision (Mike): ● All went smoothly ! Non-closure of the knobs 30 microns in V, 60 microns in H. OK ! To be implemented in the sequence 8: 30 meeting
Thursday 5. 8. ● Access request from CMS to fix serious problem on their detector ● Profited from the access for CMS to fix: – problem on MKB (vacuum interlock configuration) – Module replacement for fixing the spurious interlocks on Q 10. R 8 ● Accesses finished by 22: 45 ● Tedious injection process because of an intermittent problem with an 80 MHz cavity in the PS. 8: 30 meeting
Friday 6. 8. ● 04: 00: Fill 1263 – Physics fill with 25 nominal bunches; No tune split and DQ = +2 10 -3; – Emittances: ex 1 = 3. 4 mm; ey 1 = 3. 0 mm; ex 2 = 3. 0 mm; ey 2 = 3. 2 mm; – Initial peak luminosity of 2. 7 1030 cm-2 sec-1 (ca. 10% less then previous fill); – Beam lifetimes initially 5 h and above 25 hours after a couple of hours. – Terminated at 19: 15 Generated integrated luminosity of ca. 90 nb-1 total luminosity delivered ca. 980 nb-1 8: 30 meeting 15
Friday 6. 8. ● Feedback during ramp and squeeze: 8: 30 meeting 16
Friday 6. 8. ● Relative bunch intensity drops for Beam 1 and Beam 2: Fill 1263 8: 30 meeting 17 Giulia Papotti (BE/OP/LHC)
Friday 6. 8. ● Relative bunch intensity for Beam 1 and Beam 2: Fill 1263 no Q split & DQ = 2 10 -3 versus Fill 1262 no Q split 8: 30 meeting 18 giulia papotti (BE/OP/LHC)
Friday 6. 8. Relative bunch intensity drops for Beam 1 and Beam 2: Fill 1263 no Q split & DQ = 2 10 -3 versus Fill 1257 with Q split 8: 30 meeting 19 giulia papotti (BE/OP/LHC)
Friday 6. 8. ● Luminosity over 16 hours: ca. 50% drop over 15 hours 8: 30 meeting ~90 nb-1 20
Friday 6. 8. ● Fill terminated at 19: 00: ca. 1000 nb-1 ± 10% 8: 30 meeting 21 Champagne!!!
Friday 6. 8. ● 21: 00: Preparing new fill for the night: Fill 1264 – 21: 00: injecting pilot and setup (some delays: mastership, phasing, SPS beam quality [emittance and intensity]) start ramp around midnight – Emittances: ex 1 = 2. 4 mm; ey 1 = 2. 3 mm; ex 2 = 2. 4 mm; ey 2 = 3. 6 mm; – 01: 42: Stable beams: – Initial peak luminosity of 3. 1 1030 cm-2 sec-1; – Beam lifetimes initially 5 h and above 25 hours after a couple of hours. ● 02: 15: Beam dump (BLM in Pt 4) – Start pre-cycle machine ready for new injection at 8: 30 meeting 22
Saturday 7. 8. ● Initial Luminosities 8: 30 meeting 23
Saturday 7. 8. ● Lifetimes rising from 5 h to above 25 hours over one hour: 8: 30 meeting 24
Saturday 7. 8. ● Fill #1264 dump at 02: 14: 38: BLM @Q 11. L 4 B 1 (2. 5 ms threshold triggered). ● The comparison with a BLM at TCP. L 7 indicates that the loss is real, similar time behaviour
Saturday 7. 8. ● 04: 15: Problems resetting the machine – Can't close the switch of RQTF. A 67 B 2 called piquet and preparing for access in UA 67 (but could closed in the end by M. Zerlauth by doing "Reset System" ) ● 05: 24: Sector 67 tripped again: – Quench loop of Q 8. R 6 which opened again. – As before, a disturbance in the quench signal opens the quench loop. – Diagnosis later points to the power converter as origin for the fault ● 06: 15: A local perturbation in Pt 2 stopped the filters of the compensator; TI advises to stop sectors S 12 and S 23 + the ALICE magnets ● Spent all day in access for QPS and FGC interventions! 8: 30 meeting 26
Sunday 7. 8. ● 20: 00: Preparing fill for the night: Fill 1266 – – – Emittances: ex 1 = 2. 2 mm; ey 1 = 2. 3 mm; ex 2 = 2. 0 mm; ey 2 = 2. 5 mm; 23: 00: Stable beams: Initial peak luminosity of 4 1030 cm-2 sec-1; Beam lifetimes initially 5 h and above 25 hours after a couple of hours. Beam dumped after 2 h! This time by BLM in IR 5. ● 01: 00: Preparing new fill for night: – – – Emittances: ex 1 = 2. 5 mm; ey 1 = 2. 5 mm; ex 2 = 2. 6 mm; ey 2 = 4. 0 mm; 05: 30: Stable beams: Initial peak luminosity of 3 1030 cm-2 sec-1; Beam lifetimes initially 5 h and above 25 hours after a couple of hours. 18: 50: Loss of Cryo in S 34 (loss of communication) beam dump after 14 hours. 8: 30 meeting 27
07/08/2010 ● Relative losses for fill 1264 and 1266. – Both with NO tune split. – Both dumped after one hour due to BLM reading ● 1266 initial losses lower than in any other fill G. Papotti
Sunday 8. 8. ● 21: 00: Short Hump study at 450 Ge. V – No clear evidence yet on effect of offset in cavities on Hump activity. ● 23: 00: Preparing fill for the night: – – – Emittances: ex 1 = 2. 7 mm; ey 1 = 2. 9 mm; ex 2 = 2. 8 mm; ey 2 = 3. 9 mm; 01: 30: Stable beams: Initial peak luminosity of 3 1030 cm-2 sec-1; Beam lifetimes initially 5 h and above 25 hours after a couple of hours. 04: 00: Beams dumped: quench loop of the RB. A 67 8: 30 meeting 29
Saturday 7. 8. ● Plan for the coming days: – Luminosity fills – Next week: Test ramp with 2 bunches: – Check TCTs. – Collimator loss maps. – Beam dump validation (Dump with RF OFF) – Implementation of new beam process for establishing collisions. – 8: 30 meeting 30
Pending ● Tests: – New BLM Firmware tests – Delay of the PM trigger of the BLM system to be set back BLM team ready only next week – Loss maps, orbit clean-up and TCT verifications ● Requiring access: – Repair COD MCBH. 18 R 7. B 2 – CV need to replace a motorization of the water valve of the sector 56 not urgent – Time estimate ~3 hours – Access team to replace oxydized connectors for PAD-PX 24 in case of stop (3 hours) – Magnetic probes in the machine for the studies related to the hump access in point 5 (GA, LW) – 3 hours
Monday 9. 8. ● Open Issues: – Clogging of CMS cryo filters not yet understood – QPS boards: several boards had to switch from channel A to B. – BLM racks (in buildings SR 1 and SR 5 and both at position BY 02): would like to correct the way the power cable for the multi-plug arrives inside the rack. – Ion pumps in dump line MKB (B 2 only 4 out of 8 pumps working; few days intervention, next TS) – Origin – cause of the beam losses that terminated 2 of the best runs (beam? ; coherent versus incoherent? ). – Bunch-to-Bunch diagnostics would be very helpful! ● Week 32: – Malika and Jörg 8: 30 meeting 32
Monday 2. 8. ● 12: 35: Lost access chain in point 2 (PX 24 PAD) Dump after ~14. 5 hours ~100 nb-1 8: 30 meeting
Tuesday 3. 8. ● Sector 23 Quadrupoles tripped at 07: 39 after 7 hours and 20 mins in coast. ● Cause being investigated ~50 nb-1 ● CMS preparing to ramp down the solenoid for cryo intervention
Tuesday 3. 8. ● Beam 2 losses during over injection: Losses for Beam 2 too high for operation 8: 30 meeting 35
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