1. LHC Technical Committee, 28/03/2007 LHC Commissioning Phases 450GeV Initial Commissioning presented by Rhodri Jones (AB/BI) on behalf of the LHCCWG Particular thanks to the A. Butterworth, B. Goddard, W. Hofle, V. Kain, R. Steinhagen & J. Wenninger

2. LHC Technical Committee, 28/03/2007 LHC Commissioning Phases: Phase 3 – 450GeV Initial Commissioning Phase A.3: 450GeV Initial Commissioning – Objectives – Entry conditions – Preconditions and tools – Commissioning procedure – Exit conditions Summary

3. LHC Technical Committee, 28/03/2007 LHC Stage A: Commissioning phases PhaseDescription A.1Injection and first turn: injection commissioning; threading, commissioning beam instrumentation. A.2Circulating pilot: establish circulating beam, closed orbit, tunes, RF capture A.3450 GeV initial commissioning: initial commissioning of beam instrumentation, beam dump A.4450 GeV optics: beta beating, dispersion, coupling, non-linear field quality, aperture A.5Increasing intensity: prepare the LHC for unsafe beam A.6Two beam operation - colliding beams at 450 GeV A.7Snap-back and ramp: single beam A.8Bringing beams into collision: adjustment and luminosity measurement A.97 TeV optics: beta beating, dispersion, coupling, non-linear field quality, aperture A.10Squeeze: commissioning the betatron squeeze in all IP's A.11Physics runs: physics with partially squeezed beams, no crossing in IP1 and IP5 Phases for full commissioning Stage A (pilot physics run) Basic Objectives: Continued RF commissioning Initial commissioning of beam dump Commissioning of beam instrumentation To reach a lifetime > 1hr at 450GeV

4. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Overview of Steps Involved Steps 1 to 3 carried out with a single pilot bunch of 5×10 9 Remaining steps carried out with a single intermediate bunch of ~ 3×10 10 – higher precision on measurements & easier for BI commissioning All steps carried out first on one beam then on the other – same “experts” will be required for both systems StepActivity A.3.1Final RF commissioning with Pilot Intensity A.3.2BPM Checks with Pilot Intensity A.3.3First Commissioning of the Beam Dumping System (pilot) A.3.4Commission beam instrumentation with higher intensity A.3.5Lifetime optimisation – to get to at least 1 hour A.3.6Further commission beam instrumentation with lifetime > 1hr A.3.7Further commission beam dumping system A.3.8Commission BI Feedback Systems A.3.9Start Commissioning of TCP Collimators A.3.10Rough Setting-up of Injection Protection Devices

5. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – entry conditions Beam Entry conditions: RF Captured Beam circulating for hundreds of turns (orbit, tune & chromaticity coarsely adjusted) Additional Hardware/Software Entry conditions: Point 6, extraction channel – Dry runs and 450 GeV reliability run completed Collimator control system – TCPs, TCDQ, TCSG and TDI moveable – Collimator movements for TCP, TCDQ, IR6 TCS, TDI hardware calibrated Inject & dump / circulate & dump modes available – both scenarios hardware commissioned – timing tables available – RF synchronisation hardware tested and available Additional RF Systems – Transverse damper available Additional Beam Instrumentation – BCTDC hardware available – Interlock BPMs in LSS6 available – Tune meter & tune hardware PLL available – Tune kicker & tune tickler hardware available – Head-Tail monitor available – Wire Scanner available – Abort Gap Monitor (BSRA) available Applications & controls – XPOC GUI and analysis package available in the control room – GUIs for all RF & BI instrumentation

6. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.1 – RF (Pilot) StepActivityPriority A.3.1Final RF commissioning with Pilot Intensity.01Check bunch 1 timing with revolution frequency and abort gapRF1.02Commission the transverse feedback for injection oscillationsRF1.03Commission the wall current monitor for beam diagnosticsRF1 Further RF commissioning – Details still to be presented at LHCCWG will be put on the agenda for a future meeting Transverse damper (some preliminary comments from W. Hofle) – As an exciter the damper system will be available from day 1 – The damper pick-up electronics can be commissioned as soon as there is circulating beam – Injection damping should only be attempted once a stable tune has been established the phase advance between the damper pick-ups is reasonably well known – These 2 conditions push this towards the end of this Stage

7. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.2 – BPM (Pilot) StepActivityPriority A.3.2BPM Checks with Pilot Intensity.01Time in the BPM system with respect to RFBI1.02Commission the real-time channel for continuous orbit measurementBI/OP1.03Rough calibration of BPM & corrector systemST/OP1.04Flatten orbit in injection regions and dumping regionST1 Time-in the BPM system with respect to RF – Adjust BST for all crates to get same turn on all systems – Put bunch 1 in bucket 1 for all channels (automatic but requires checks) – Adjust the 40MHz phase for each channel (automatic but requires checks) Commission the real-time channel for continuous orbit measurement – Orbit data concentration initially at 1Hz – First step in setting up orbit feedback Scan a few orbit correctors & acquire all monitors – Allows check on BPM quality and calibrations. – Measurements require only 4-20 correctors/plane/ring – Use response data for first rough linear optics check phase advance measurements are ‘lighter’ and faster to fit Flatten orbit in injection regions and dumping region

8. SPS example : before fit ( * ) + line : model Histogram : raw data MDHD.118MDV.121 Since the SPS lattice is very simple, the model tune is set far away (0.2) from the actual tune in the example to make life a bit more difficult for the fit. Response for a horizontal and a vertical corrector (1% of the matrix). J. Wenninger – LHCCWG June 2006

9. SPS example : a few fit iterations later… MDHD.118MDV.121 Histogram : gain corrected data Empty bin  BPM rejected ( * ) + line : fit model (17 MAD parameters) with calibrated kick BPM and correctors are calibrated. Fitted model tunes exactly as expected ! Excellent agreement model-data. Details on SPS results can be found in CERN-AB-2004-009 J. Wenninger – LHCCWG June 2006

10. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.3 – Beam Dump (Pilot) StepActivityPriority A.3.3First Commissioning of the Beam Dumping System (pilot).01Set mode circulate & dump (1 s delay - depends on lifetime?)ST1.02 Set TCDQ and TCS in IR6 to ~10  using nominal optics & orbit info ST/OP/ATB1.03Check analogue signal from kicker trigger BPMs is correctly transmittedBI/BT1.04Adjust kicker timing with single pilot as bunch #1BT1.05Aperture measurements with circulating beamOP1.06Commission dump line Beam InstrumentationBI1.07Check bunch dumped on TDE blockBT1 Set TCDQ & TCS – Adjust to best guess 10  based on current optics model & measured orbit – Requires collimator controls & application

11. B.Goddard ICFA-HB200611/2630 May 2006 Risk from particles in the abort gap Asynchronous beam dump or over-populated abort gap  quench or damage –Several failures possible (synchronisation, MKD erratic, abort gap repopulation) Precautionary measures include: –Abort gap watchdog during the injection process, to inhibit injection with wrong phase –Abort gap monitor and possibility of abort gap cleaning –TCDS (fixed) – 6 m long diluter protects extraction septum –TCDQ/TCS (mobile) – 7 m long diluter kept at about 7-8  from the beam, at all times

12. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.3 – Beam Dump (Pilot) StepActivityPriority A.3.3First Commissioning of the Beam Dumping System (pilot).01Set mode circulate & dump (1 s delay - depends on lifetime?)ST1.02 Set TCDQ and TCS in IR6 to ~10  using nominal optics & orbit info ST/OP/ATB1.03Check analogue signal from kicker trigger BPMs is correctly transmittedBI/BT1.04Adjust kicker timing with single pilot as bunch #1BT1.05Aperture measurements with circulating beamOP1.06Commission dump line Beam InstrumentationBI1.07Check bunch dumped on TDE blockBT1 Set TCDQ & TCS – Adjust to best guess 10  based on current optics model & measured orbit – Requires collimator controls & application Aperture Measurements – Horizontal aperture at TCDS entrance & MSD exit – Horizontal and Vertical aperture at MSD Commission dump line Beam Instrumentation – BLMs, BPMs, BTVs & FBCTs – check all beam-dependent transient signals are acquired correctly for XPOC Check position of bunch dumped – adjust energy tracking if needed  local intervention to change EPROMS – adjust IPOC/XPOC references if needed

13. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.4 – BI (Pilot ++) StepActivityPriority A.3.4Commission beam instrumentation with higher intensity ~ 3 x 10 10 3.4.10 Full BCT Commissioning.11Commission the BCTDC with beam to give acquisitions updates at 1HzBI1.12Commission the Safe Beam Flag using the BCTDC measurementBI/OP/CO1.13Commission the BCTFR in bunch to bunch modeBI1.14Commission the Beam Presence Flag using BCTFRBI/OP/CO1.15Commission the BCTFR lifetime measurementBI1.16Cross calibrate the BCTDC and BCTFRBI2 Commission Safe Beam Flag using 1Hz BCTDC intensity measurement – Verify the generation & distribution – Verify the logic at the LHC master BIC concerning the LHC safe beam flag Commission the BCTFR in bunch to bunch mode – Set slot 1 to correspond to bunch 1 – Adjust the phase of the acquisition Commission the Beam Presence Flag using BCTFR – Verify the generation & distribution Commission the lifetime measurement – Will use turn by turn data from the BCTFR to calculate the lifetime – Lifetime initially updated at 1Hz

14. Third LHC Project Workshop, January 2005 - Rhodri Jones (CERN - AB/BI) Measurement Mode Beam type Accuracy/ Resolution Fast BCT (BCTFR) DC BCT (BCTDC) Injection Pilot bunch±20% / ±20% ±10 9 (OK) N/A Nominal bunch ±3% / ±1% ±3·10 9 / ±10 9 (OK) N/A Circulating Beam (>200 turns) Pilot bunch±10% / ±10% ±0.5·10 9 (OK) 1  A (on 10  A) (resolution ~2-10  A) Nominal bunch ±1% / ±1% ±10 9 (OK) 2  A (on 180  A) (limit for short int time) 43 pilot bunches ±1% / ±1% ±10 9 (OK) 2  A (on 390  A) (limit for short int time) Lifetime Pilot bunch 10% (10hrs/1min) (OK)N/A Nominal bunch 10% (30hrs/10sec) (OK)N/A Early LHC BCT System Performance

15. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.4 – BI (Pilot ++) StepActivityPriority A.3.4Commission beam instrumentation with higher intensity ~ 3 x 10 10 3.4.20 Tune Meter Commissioning.21Commission single kick tune measurement using MKQ & BBQBI/BT1.22Commission chirped tune measurement using BQK & BBQBI1.23Commission chirped tune measurement using transverse damperBI/RF2.24Commission head-tail chromaticity measurementBI1.25Commission the BCTFR lifetime measurementBI1 3.4.30 Initial BLM system commissioning.31Adjust thresholds on "quench & learn basis"BI/ST1.32Lose / quench on purposeBI/ST2 Commission the Tune Meter – Time-in the MKQ tune kicker – FFT analysis after applied excitation MKQ – dedicated Q kicker Chirp – either via BQK (BI tickler) or transverse damper Commission Head-Tail Monitor – In parallel to Tune Meter with MKQ excitation – Allows more precise chromaticity measurement Initial BLM System Commissioning – At this stage perform threshold adjustment on an “accidental quench & learn” basis – If quenches are very frequent then a more detailed study may be necessary determine quench level for type of magnet which is quenching by steering beam into magnet?

16. LHCCWG, April 2005 - Rhodri Jones (CERN - AB/BI) BLM System at 450GeV Already Commissioned  Hardware functionality & detector availability First Adjustment of Thresholds  Initially set as factor 3 below estimated quench level at 450GeV Based on –simulations –lab heating test measurements (SM18) –possible sector test data Thresholds adjusted either on a –Quench & learn basis if too high –Dump & learn basis if too low Threshold change procedure under discussion in MPWG  At 450GeV fast loss damage level is factor 1000 above quench level No risk of damaging components

17. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.5 – Lifetime (Pilot ++) StepActivityPriority A.3.5Lifetime optimisation – to get to at least 1 hour ~ 3 x 10 10.01Adjust orbit, tune, chromaticity & couplingST1 Lifetime Optimisation – Use commissioned beam instrumentation to achieve reasonable lifetime required for commissioning of remaining instrumentation required for detailed optics measurements in next commissioning step

18. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.6 – BI (lifetime >1hr) StepActivityPriority A.3.6Further commission beam instrumentation with lifetime > 1hr ~ 3 x 10 10 3.6.10 Systematic BPM & Corrector Calibration.11Scan all orbit correctors and acquire all monitors - polarity and calibrationBI1 3.6.20 Commission PLL Tune & Coupling Measurement BI1 3.6.30 Commission Wire Scanners BI1 3.6.40 Commission Synchrotron Light monitors BI1.41Commission the undulatorsST1.42Commission the abort gap monitorBI1.43Commission the synchrotron light beam size monitorBI2 3.6.50 Commission Rest Gas Ionisation Monitor BI2.51Commission the gas injection systemBI/VAC2 Systematic calibration of the BPMs & Correctors – Scan all orbit correctors and acquire all monitors ~30 s per COD (530 CODs per beam)  ~1 shift per beam – Check response data for BPM & COD polarities and calibrations – Use response data for a more detailed linear optics check PLL – Requires BQK tune tickler or transverse damper in excitation mode Wire Scanners – May need to slow them down to get desired resolution on a single bunch 2m per second  180  m per point Abort Gap – Commission the optics – will require tunnel intervention for fine adjustment – Define and check timing and injection bucket – Calibrate photon production versus proton number using a single bunch – Set threshold based on quench level in terms of protons/meter

19. LHC Machine Advisory Committee December 2006 - Rhodri Jones (CERN - AB/BI) Abort Gap Monitor (BSRA) System based on gated photomultiplier Tested in the SPS with synchrotron light source on fixed target beam  Observation of injection kicker gap while beam is debunched before extraction. Worked extremely well Gain of photomultiplier is not as high as advertised  Requires 15x more light For LHC a longer integration time is possible (every ms for SPS) BUT BSRA will require more light than anticipated at expense of BSRT

20. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.7 – Detailed Dump StepActivityPriority A.3.7Further commission beam dumping system ~ 3 x 10 10.01Commission beam dependent interlocksST/BI/CO1.02Perform detailed aperture measurements around extraction regionOP/BT1.03Perform detailed aperture measurements in the dump lineOP/BT1.04Adjust fine kicker timingBT1 Commission Beam Dependent Interlocks – Verify beam position interlock in IR6 (set to dump at > 3.2mm) – Verify count rates on BLM monitors at TCDQ (hardware link to dump) Aperture Checks in IR6 – H: TCDS entrance, MSD exit, TCDQ, TCS – H&V: MKD, MSD, TCDQM (retract TCDQ) Aperture Checks in the Dump Lines – Explicit check to ensure aperture is adequate for 14/15 MKD – Requires orbit bump in IR6 (cannot unplug 1 MKD) Adjustment of Fine Kicker Timing – 2 bunches (bunch 1 & 2808) to define abort gap Needs ‘new’ injection sequence and timing tables – UA access will be required for each trim

21. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.8 – Feedbacks StepActivityPriority A.3.8Commission BI Feedback Systems ~ 3 x 10 10.01Commission RF radial modulationRF1.02Commission continuous chromaticity measurementBI1.03Commission Orbit FeedbackOP/BI1.04Commission Tune & Coupling FeedbacksOP/BI1 Commission Continuous Chromaticity Measurements – Requires RF radial modulation to be operational (~1Hz modulation) – Optimise PLL to track tune modulation of 1×10 -4 Commission Orbit Feedback – Use measured BPM & corrector calibrations – Use “best guess” optics model Convergence time (i.e. correction rate) will depend on accuracy of the model Commission Tune & Coupling Feedback – Verify trim quadrupole calibration (16 circuits per beam) – Verify trim skew quadrupole calibration (12 circuits B1 & 10 circuits B2) – Robust tune feedback requires coupling to be corrected! Using commissioning tunes should help: 64.285/59.385

22. Third LHC Project Workshop, January 2005 - Rhodri Jones (CERN - AB/BI) Measurement of Coupling using a PLL Tune Tracker (RHIC Example) Fully coupled Tunes entirely defined by coupling

23. LHCCWG, April 2005 - Rhodri Jones (CERN - AB/BI) Coupling Feedback at RHIC (2006)

24. LHC Technical Committee, 28/03/2007 450GeV Initial Commissioning – Stage A.3.8 – Feedbacks StepActivityPriority A.3.9Start Commissioning of TCP Collimators ATB/OP2 A.3.10Rough Setting-up of Injection Protection Devices BT/OP1 Start the commissioning of some collimators (TCPs) – Find the orbit position at the primary collimators and assign the aperture based on the best available optics estimates Initial setting roughly 10 sigma Rough setting up of injection protection devices – Find the orbit position at the protection devices and assign the aperture based on the best available optics estimates. – Lock the orbit with orbit feedback – Verify the centring of the TDI with circulating beam requires masking of BLM thresholds at TDI – Set TDI to 10 sigma with the measured optics information – Set TCLI to 10 sigma with the measured optics information

25. LHC Technical Committee, 28/03/2007 Summary Phase A.3 : – from a few hundred turns of circulating beam to a lifetime > 1 hr. Main focus is on: – Continued RF commissioning – Initial beam dumping system commissioning – Full beam instrumentation commissioning Consensus is to include time for commissioning of feedbacks at this stage Ramp development is much easier if these feedbacks are operational – Basic optics measurements At the end of this stage the machine should: – be ready for detailed optics measurements at 450GeV (next step) – have beam instrumentation and RF ready for ramping