1. LHC Collimation Working Group – 02 April 2012 Results from Beam-Based Collimator Alignment G. Valentino, R. W. Assmann, R. Bruce, F. Burkart, M. Cauchi, D. Deboy, L. Lari, S. Redaelli, B. Salvachua

2. Outline Gianluca Valentino2 The collimator setup application Fast BLM data acquisition Software issues encountered during the setups Results comparison: 2011 vs. 2012 Qualification of the collimator settings Summary

3. Reminder: collimator setup application Gianluca Valentino3 Setup Task Sequencer GUI User Parallel Setup Algorithm Loss Threshold Selection BLM Spike Recognition Fast BLM Data Acquisition BLM Feedback Structure as proposed for March 2012 setups

4. 12.5 Hz BLM data acquisition Gianluca Valentino4 cs-ccr-logging2 cs-ccr-dev Thanks to: R. Assmann, V. Baggiolini, A. Bland, B. Dehning, S. Jackson, S. Redaelli, C. Zamantzas CCC Setup Application Fast BLM Data Logging ~3900 BLMs in all crates 12.5 Hz and 1 Hz BLM signals Left jaw aligned Right jaw aligned

5. Issues encountered during setups Some software issues were encountered in the 450 GeV setup, which were fixed by the 4 TeV setup: -Fast BLM data was transmitted from the low-level with channels & crates in reverse order for each IR. -GUI: multi-threading issues prevented full functionality of GUI. -Sequencer not jumping correctly through the setup stages (TCP, parallel, sequential). -Setup Sheet: left and right jaw positions not saved correctly. Outstanding issues: -Loss spike recognition: All clearly optimal spikes (e.g. TCP IR7) were classified correctly. -Main issues were for “grey area” spikes: in the classifier design, it was preferred to err in classifying an optimal spike as non-optimal rather than classifying an non-optimal spike as optimal. -When detecting a non-optimal spike, the jaw is moved in once again until an optimal spike is classified. This could cause dumps at 4 TeV if the jaw is at the beam and is moved in erroneously again. -Algorithm assumes a simple loss spike model with a low noise level, no other spikes after main spike, etc. -An improved spike recognition algorithm will be developed and tested in an MD. Beam instabilities: possible impedance effects with too many collimators close to the beam (N. Mounet) Gianluca Valentino5

6. Alignment results: setup time Setups in March 2012: Comparison in setup time 2010 – 2012 for the full system: Gianluca Valentino6 2010 (Manual)2011 @ 1 Hz2012 @ 8 Hz 450 GeV3.5 TeV450 GeV3.5 TeV450 GeV4 TeV # Fills356331 # Dumps142000 # Hours112818.517.7107.5 Setup TypeInjectionFlat TopCollidingSqueezed Date21 st March 29 th March30 th March31 st March

7. Alignment results: beam-based centres Beam-based centre comparison to 2011 for injection orbit. Gianluca Valentino7 µ = 0.177 mm σ = 0.033 mm µ = 0.177 mm σ = 0.033 mm µ = 0.229 mm σ = 0.076 mm µ = 0.229 mm σ = 0.076 mm Delta: 450 GeV 2011 vs. 2012 B1 and B2Delta: Flat Top 2011 vs. 2012 B1 and B2 ∆ TCLIA.4R2 = -12.920mm ∆ TDI.4L2 = +7.048mm ∆ TCLIA.4R2 = -12.920mm ∆ TDI.4L2 = +7.048mm

8. Alignment results: beam-based centres Gianluca Valentino8 µ = 0.238 mm σ = 0.111 mm µ = 0.238 mm σ = 0.111 mm µ = 0.183 mm σ = 0.059 mm µ = 0.183 mm σ = 0.059 mm Beam-based centre comparison between 450 GeV and 4 TeV in 2012 (injection orbit). Delta: 450 GeV vs. 4 TeV B1Delta: 450 GeV vs. 4 TeV B2

9. Alignment Results: Beam Size Ratios Beam Size Ratio comparison: 2012 vs 2011, 450 GeV Gianluca Valentino9 IR2IR3IR7 IR8 IR3 IR7 TDI

10. Alignment Results: Beam Size Ratios Beam Size Ratio comparison: 2012 vs 2011, Flat Top Gianluca Valentino10 IR3IR7 IR3 IR7

11. Collimator Settings Qualification Gianluca Valentino11 B. Salvachua LIC BLMs

12. Collimator Settings Qualification Gianluca Valentino12 B. Salvachua

13. Summary Collimator setup time reduced from 17 hours in 2011 to 7.5 hours in 2012 at flat top, 1 fill. Limit for setup time not yet reached: improvements can still be made. Further tests will be carried out in an 8 hour slot in April MD. Future Work: Only GUI will run on CCC console: BLM feedback and jaw movement requests to be moved to a server. Distributed application will be developed based on Java RMI and JMS, running on the server and the CCC console. More complex beam loss recognition system to be designed. Gianluca Valentino13