1. RF Systems Commissioning O. Brunner AB/RF on behalf of the RF group (LTC – March ’08) Many thanks to L. Arnaudon, Ph. Baudrenghien, W. Hofle, D. Valuch, J. Molendijk, A. Butterworth, F. Dubouchet, Ed. Ciapala, U. Wehrle, T. Bohl, P. Maesen, V. Rossi, M.E. Angoletta, E. Montesinos for their help 1obrunner, LTC March'08

2. Summary 400 MHz superconducting cavities (ACS) RF dampers (ADT) Pick ups & RF instrumentation RF synchro & beam control 2 obrunner, LTC March'08

3. ACS – LHC accelerating system 100kV- 40A power converter HV switch mod 1mod 2mod 3mod 4thyratron4uF capacitor kly circ control systems: -interlocks -specialists applications -supervision  made up of:  4 4MW power converters  16 RF power stations (HV equipment, 330kW klystrons, circulators, RF loads, WG)  16 superconducting cavities (4 cryostats) kly circ kly circ kly circ cavities 3 obrunner, LTC March'08 Low level RF system

4. warm commissioning (WG short-circuited) 1. High voltage commissioning: switch on tests (AB/PO) control interlocks operation: 10kV services cooling (air, water) control interlocks DCCT klystron (focus,...) crowbar (spark gap)  Still to be done (in March)  test with all 4 power converters full power in parallel  test&calibrate TS/EL equipment  optimize HV ripple (600Hz)  test spare power converter  test spare HV cables (surface to tunnel) 4 obrunner, LTC March'08 operation: 58kV klystrons current control crowbar (ext. trigger @ 62kV) klystron heaters set up DC power calibrations thermal power calibration RF switch ON RF calibrations 2. RF commissioning: RF interlocks RF calibration klystron protection RF pre-amplifier Circulator temperature control unit 300 kW RF power tests klystron saturation curve Klystron freq response group delay meas.  Status:  done on 15/16 RF power stations  To be finished in March

5. cold commissioning – status of sector 4-5  Access & RAMSES systems tested & validated  2 modules (sect 4-5) successfully cooled down in November  Cryogenics system  Excellent cryogenic regulations (level&pressure) in the modules  Several cryo control system communication problems (  He lost through modules safety valves)  So far no direct impact of magnet quenches on RF cavities  Low RF power tests of 8 cavities done  Mechanical Tuner range of 8 cavities measured&Q measurements performed  Parallel conditioning of eight cavities up to:  1MV/cavity with main coupler position1 (Q L = 20’000)  2MV/cavity with main coupler position 2 (Q L = 60’000)  Radiation measurements:  Peak value: few mSv/h close to the cavities (8 cavities running in //)  Might get higher radiation above 2MV  No radiation measured nor in UX45 nor outside the RF zone five weeks of “conditioning” (~1 ½ wk per cavity) Main issues: frequent stops due to accesses in RF zone, UX45 (w/o film badges..) logging system (Timber) not fully operational 5 obrunner, LTC March'08

6. Set up the Klystron drive limiter  to prevent driving the klystron over the saturation limit during loop transients Set up the Tuner Loop  to keep the cavity on resonance Set up the Klystron Polar Loop  to compensate the variation of klystron power and phase shift (by e.g. caused by high voltage supply ripple 600Hz). Set up the RF feedback  to keep the accelerating voltage at the desired value in the presence of transient beam loading  later: 1 turn feedback  condition: cavities & main couplers must be fully conditioned  successfully done on 3 cavities  after training: 2-3 days of work/cavity cold commissioning – low level RF set up more results will be presented by Ph. Baudrenghien Vcav Feedback Closed. 25 kHz span, 30 Hz BW Phase Noise Vcav-Ref RF fdbk open ~4 dg pkpk, fdbk closed ~0.3 dg pkpk @1MV CW Phase Noise Vcav-Ref RF all loops closed ~0.1 dg pkpk @1MV CW 6 obrunner, LTC March'08

7. Low Level RF hardware equipment - status System Item Hardware Ready - Installed FirmwareDriversFESAApp. SW Expected ready for startup ACS Automatic conditioning system Yes Cavity Controller RF Modulator/Klystron polar loop Yes Cavity Controller Switch/protection module Yes Cavity Controller RF feedback Yes Cavity Controller Setpoint module Yes Cavity Controller Clock generation Yes Cavity Controller Clock distribution Yes Cavity Controller Analogue demodulator Yes (Passive, no control) Cavity Controller 1 turn feedback Yes Cavity Controller Conditioning DDS Yes Cavity Controller Tuner RF Front end Yes Cavity Controller Tuner Control Yes ACS High-level Logic & Interface to LSA Yes Not yet started In progress Completed 7 obrunner, LTC March'08

8. ACS system commissioning - status  cavities cold & ready for RF ~ mid-May  expected commissioning time: ~ 6-8 weeks  cavities cold & ready for RF ~ mid-June  expected commissioning time: ~ 4-5 weeks 8 obrunner, LTC March'08 Sector 4-5 Sector 3-4

9. ADT (dampers) system Damper essential to avoid increase of transverse emittance pick-up 1 Kickers Real time digital signal processing pick-up 2 feedback: curing transverse coupled bunch instabilities (becomes important with increasing intensity) excitation: of transverse oscillations for beam measurements & other applications (e.g. tune meas) damping: of transverse injection oscillations Amplification 9 obrunner, LTC March'08

10. ADT racks (driver amplifiers, PLC controls, fast interlocks) ADT (4 modules) left of IP4 + space for 2 more modules (upgrade) ADT (4 modules) right of IP4 + space for 2 more modules (upgrade) Beam 1 Beam 2 SR4 (surface): Signal Processing electronics (VME crates) HV Power Converters PLC controls 8 Dedicated Pick-ups BPMC @ Q7L, Q7R, Q9L, Q9R ADT system - layout 10 obrunner, LTC March'08

11. ADT (dampers) commissioning - status end of power commissioning: March SystemItemHardwareFirmwareDriversFESA App. SWExpected ready for startup ADT PowerPLC controls Yes ADT Low levelTransverse feedback Yes (on the critical path) ADT Low levelADT radial position acquisition Yes (on the critical path) ADTHigh-level logic & interface to LSA Yes 11 obrunner, LTC March'08

12. RF Beam Observation Status APWL Pick-Ups  6 pick-ups in LHC tunnel (4 for RF Group, 2 for BI Group) all installed  pick-up combiners not yet installed (soon) Instrumentation  instruments for RF Beam Observation all installed  digital acquisition cards for RF Beam Observation, UX45 all installed  digital acquisition cards for RF Beam Observation, SR4 not yet installed  modules for peak detector (VME) under construction  software for Mountain Range, low frequency signals (OASIS) under test  software for bunch profile acquisition and analysis not yet implemented SystemItemHardwareFirmwareDriversFESAApp.SWExpected ready for startup Beam ObsSignal distribution switching Yes Beam ObsDetected signals (100MS/s) Yes, minimum functionality Beam ObsInjection MR (8GS/s) Yes, minimum functionality Beam ObsBunch length measurement (8GS/s) Yes, minimum functionality 12 obrunner, LTC March'08

13. RF synchro & beam control beam control loops modules beam phase modules (rigid and precise, for final use) vector sum ACS cavities wide band pick-up (APW) beam radial strip line pu (Q10) bunch amplitude bunch phase voltage seen by each bunch beam phase averaged voltage seen by bunch phase pu signal frequency program f RF reference radial loop (for initial commissioning when ramp is not very reproducible ) stable phase radial position fiber optic link to CCC, CMS, AB/BT... bunch freq F rev to longitudinal damper 10MHz (GPS) tempo 13 obrunner, LTC March'08 Status:  Distribution of fast clocks to the experiments (Frev, 40 MHz) :  Installation of Fiber Optic Transmitter and Receiver modules underway.  Prototype link tested OK (S. baron, PH dept)  Distribution of Frev and kicker pulses to BI and BT:  installation of TX/RX underway  Installation of the RF Synchro modules in SR4 to generate Frev and kicker pulses:  starting end March  Link with the SPS: commissioning end March- begin April Aim: all commissioned by mid April

14. RF synchro & beam control SystemItemHardwareFirmwareDriversFESAApp. SWExpected ready for startup All VME crates Crate Management Unit Needed - critical RF Synchro Trigger unit Yes RF Synchro Injection pulse generator Yes RF Synchro Dual wideband switch Yes RF Synchro Dual wideband demux Yes RF Synchro 400 MHz phase shifter Yes, minimum functionality RF Synchro Optical Tx analog Yes RF Synchro Optical Rx analog Yes RF Synchro Optical Tx digital Yes RF Synchro Optical Rx digital Yes RF Synchro Synchro Loop (Phase Synchro) Yes Beam control Frequency Program DDS Yes Beam control VCXO Yes, minimum functionality Beam control Beam phase measurement Yes, minimum functionality Beam control Beam position measurement Yes, minimum functionality Beam control Low level loops DSP Yes Beam control LL Loops Interface Yes Beam control Beam parameters DSP No (Postponed 2009) Beam control Longitudinal feedback No (Postponed 2009) 14 obrunner, LTC March'08

15. Conclusions 400 MHz superconducting cavities (ACS)  High RF power stations commissioning comes to an end  8 cavities & main couplers conditioned  LL RF setting up successful so far Objective: get all LL RF modules + related SW ready&tested for next cool down  Should be ready for beam on time (if not suffering from too many accesses in RF zone) RF dampers (ADT)  Power commissioning almost finished  Critical: LL RF modules + related SW Pick ups & RF instrumentation  Good shape RF synchro & beam control  Well advanced  Some LL RF modules + SW on the critical path 15 obrunner, LTC March'08