1. LHC Progress Thursday 29 th October 2015 Coordination Week 44: Massimo Giovannozzi, Wolfgang Hofle, Jorg Wenninger

2. Wednesday, 28 th October 2015 Fill 4540 (SB 12h30’) – First fill with 2244 bunches – Intensity on low side, emittances on high side 4.2x10 33 peak lumi (ATLAS) 12:40 Bunch flattening at 1 ns bunch length 15:00 OP dump (clean) 16:00 MKI.B1 & PS cavity (total 30’) 17:00 injecting probe beam – Quick cryo stabilisation after dump 18:00 ramping for loss maps in preparation of quench test MD, nominals + probes – Relaxed settings for IR7, IR6 29/10/2015 LHC Morning meeting – WH & JW 2

3. Wednesday, 28 th October 2015 2 nd ramp needed – beam lost at flat top while moving collimators (SBF setting not correct) 21:20 strength of ADT for loss maps insufficient for V plane for opened collimator, ADT expert called (G. Kotzian) – 20 MHz flat bandwidth filters implemented for the cleaning reduce peak kick strength – Gerd loaded filters coefficients to permit higher kick strength – Reverted by OP after loss maps Finished with a beam 2 off momentum loss map 29/10/2015 LHC Morning meeting – WH & JW 3

4. Wednesday, 28 th October 2015 Fill 4545 (SB 3h) – 2 nd Fill with 2244 4.8x10 33 peak lumi (ATLAS) – Preparing takes time (1h50), steering lengthy (1 train of 12 only) – TDI B1, losses: 70% of dump threshold – higher bunch intensity than Fill 4540 – 10% more heat load than 4540 (same #bunches) – Point 2 cryo cold box emptying quickly (stabilised at 46%) – Q feedback and cleaning interference in squeeze – Lumi scans IP1 and IP5 not correctly stopping at max 6:20 Totem Roman pots in 7:05 dumped by CIB.USC55.R5.B1, 120 A (orbit correctors) – RPLB.RR57.RCBCH9.R5B1 29/10/2015 LHC Morning meeting – WH & JW 4

5. Wednesday, 28 th October 2015 29/10/2015 LHC Morning meeting – WH & JW 5 >1.1x10 11 p/bunch Before ramp: 3  m Fill 4545 (2244 bunches)

6. Last 24 h 29/10/2015 LHC Morning meeting – WH & JW 6 4.8x10 33 peak (ATLAS) 4540 4545

7. Bunch Flattening (fill 4540) bunches were flattened in the core without losses bunch profiles are more symmetric on B2 FWHM bunch length increased from 1.0 ns to 1.42 ns (B1) and 1.32 ns (B2) there is a step in luminosity during the application of the flattening evolution of luminosity with flattened bunches to be observed and compared to Gaussian bunches bunch profiles to be observed again before dumping 29/10/2015 LHC Morning meeting – WH & JW 7 RF Team Reminder: Fill 4538, bunches unstable below 0.85 ns  length increasing steadily

8. Bunch Flattening 29/10/2015 LHC Morning meeting – WH & JW 8 some reduction on lumi seen 5% / ~ 0.15x10 33 but no optimization (lumi scan done) to be checked what fraction from abort gap cleaning from geometric factor or simply offset 3x10 33 2x10 33 ATLAS CMS

9. Fill 4540 29/10/2015 LHC Morning meeting – WH & JW 9 preliminary Bunch length Lumi Cleaning beam 1

10. Availability 24h 29/10/2015 LHC Morning meeting – WH & JW 10 4540 (OP dump) (2244b) 4545 (2244b) MKI B1 PS (RF) Preparation of Quench test MD (Loss maps)

11. Issues in IP2 – Fill 4540 29/10/2015 LHC Morning meeting – WH & JW 11

12. Plan Continue with 2244b, bring back bunch intensities  done Preparation of quench test MD: loss maps with relaxed collimator settings  done, check loss maps Test of 2.51 TeV cycle - settings ready  next Second test with asymmetric filling (1825b in B2, 12b in B1) BCMS when CMS is back MD End of run last minute test requests roll in: – Injection with inverted tunes (0.31/0.28) to understand the source of electron cloud (dipoles/quads) – e-cloud team. – 50 Hz from PCs – G. Arduini 29/10/2015 LHC Morning meeting – WH & JW 12

13. To do list 29/10/2015 13 8b4eDone short fill SB & 1593b to FT BCMSType test ADT full bandwidthGA request  skip ? ULO scanTowards the end Reference heat loadBefore TS3 Check deconditioning at 450 GeVAfter TS3 Heat load with single beams to FTB1 done, B2 1824b with wire scans in B1 with 12 bunches Bunch flattening tests in SBDone First look at 2.51 TeVPrep. for pp reference run DoubletPushed to 2016 LHC Morning meeting – WH & JW