RF Commitments and Major Issues E. Ciapala Input from: P. Baudrenghien, O. Brunner, T. Bohl, A. Butterworth, W. Höfle, T. Linnecar, E. Shaposhnikova, J. Tückmantel Session 03 - The minimum workable LHC – providers' commitments LHC Performance Workshop Chamonix XV Divonne January 2006

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 2 RF Commitments and Major Issues Review of equipment, responsibilities and status Status for hardware commissioning & sector test Operation with beam – pilot beam Stage 1 – 1x1 to 156x156; to ( 18 uA to 25 mA ) Review of basic functionality to be provided – injection/ramping/flat top Tests, measurements and equipment to provide for first beams Subsequent stages of beam commissioning Stages 2 to 4 75->25ns->nominal (70mA to 0.57A) Machine protection Feedback loops Other functionality needed RF issues Conclusions

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 3 Review of RF Equipment – (1) Commitment – provide operational acceleration, TD and wideband PU systems ! EquipmentPersons responsibleStatus - comments ACS 400MHz SC cavities and power couplersP. Maesen, E. Ciapala E. Montesinos 4 SC modules to be in for HwC, 3 / 4 power tested. Have had delays. Mechanical modifications – tuning, cryo but going on in parallel to SM18 testing. Critical ! Just in Time for June/July installation & vacuum connection, cryo connection August….. ACS 400 MHZ RF Power and HV equipmentO. Brunner, G. Pecheur16 klystrons, HV equipment, waveguides. All needed for HwC, on schedule ADT kickers and amplifiersW. Hofle, E. Montesinos16 kickers & amplis 32 tetrodes, JINR collab. Power supplies, drive amplifiers. All to be in for HC. Come on well recently - on schedule UX45/RUX 45 installationO. BrunnerInfrastructure, general services, RF equipment, cabling. On schedule in spite of many difficulties Major part of RF equipment needs to be in place for Hardware Commissioning and be made operational by the end

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 4 UX45/RUX 45 installation Aug 2005 Jan 2006 Integration Layout

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 5 Review of RF Equipment – (2) EquipmentPersons ResponsibleStatus - comments APW wideband pick-upsT. Bohl, E. MontesinosPrototypes made, series production soon Low level RF for ACS Beam control for ACS and ADT P. Baudrenghien, W. Hofle>40 VME crates, >200 modules in ~15 different types. Over 90 % needed for HC, mainly ACS loops in UX45 but also some in SR4. Tight planning + Manpower issues Critical ! Minimal beam control system for pilot Additional requirements from then on… (See later) Synchronization and fast timingP. BaudrenghienFast timing, triggers & distribution. Tight schedule, sector test needs ? (See later) Controls hardware and software, diagnosticsL. Arnaudon, A. ButterworthControls HW & PLCs for all above equipment - on schedule. Min software set (front end software + applications) needed for HwC – coming into place.

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 6 RF System - Minimum Operational Functionality – Pilot Beam (1) Colours Green – AB-RF Black – Joint Blue – Machine test Continuously through cycle (Injection to Beam Dump) RF System equipment ACS ADT running Controls, input to Logging, alarms, PM systems (AB RF) Basic Logging, alarm and Post Mortem systems infrastructure (AB-OP AB-CO) Data Processing, PM & trip diagnostics statistics specifically for RF (AB-RF/CS + AB-CO?) Feedback loops – ACS cavity tuning, ACS RF feedback, Klystron polar loop Basic set up to be done during hardware commissioning (AB-RF) Minimum RF beam control - phase loops, synchro loop, radial loop (AB-RF) Will need careful set up with pilot, monitoring and set up for each subsequent stage Bunch signals, transverse signals - visible in CCC ! (AB-RF, AB-OP,AB-CO)

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 7 RF System - Minimum Operational Functionality – Pilot beam (2) Synchronization and Injection Signal processing and feedback for injection damping (ADT) Will need set up with beam Synchronization of injectors, SPS re-phasing before injection.. (AB-RF) Pulses for SPS extraction and LHC injection kickers (AB-RF) F revolution signals to beam dumps (AB-RF) Synchronizing loop for the two rings after injection (or flat top) (AB-RF) Slow timing (AB-CO) Overall injection control application to handle equipment set up/sequencing/bucket selection/GM timing/beam quality monitoring, + test programs etc) Control interfaces and FESA classes for the RF equipment above – (AB-RF) Complex and critical system involving many people …… ISSUE: Sector test – ‘Bricolage’ or towards final hardware ? (Many arguments for the latter..)

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 8 RF System - Minimum Operational Functionality – Pilot beam (3) Ramping RF beam control hardware (phase, synchro, radial loops) (AB-RF/FB) Function generators (ACS Volts on 16 cavities), frequency B1 B2, ADT gains..) Use of AB-PO FGCs: Control interface (AB-RF with AB-PO) Local software (AB-PO, AB RF/CS) Ramp control application (AB-OP/CO) Chromaticity / Tune measurements – radial steering (Max 300Hz aperture sweep at injection ) Via frequency program, programmed shift during ramp stop possible - Handled like any other trims - in software applications? - The frequency generator is designed to accommodate the required frequency swings (Note ~1 kHz inj->top & 7 kHz for ions) (AB-RF) - Input for feedback systems, technically possible but… External Excitation via ADT kickers – Signals from AB-BDI either in SR4 in processing loop, or directly on kickers – inputs for both provided (AB-RF) Flat top R1 and R2 40 MHz and Frev, clock signals to the experiments (AB-RF, with help from PH-ESS)

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 9 Measurements systems needed from RF - Pilot Beam & initial operation First beams - RF Off De-bunching time measurements, (3 ms for √2 inc in bl, 42 ms for 25 ns) Bunch length – APW + ‘scope or fast acquisition modules.. (2ns bunch length, 2 GHz APW bandwidth => 2 GHz 4-8 Gs/s acquisition board ) (AB-RF, AB-CO support - OASIS) Phase slip wrt RF nominal – can use phase loop or identical hardware (AB-RF beam control) RF On Lifetime measurements – APW again (AB-RF) Qs measurements Via phase loop + some processing (FFT) ! Signal quality vs loop gain – continuous or short interval measurements? – noise excitation ? To test with first beam Via peak detector and spectral analysis => measure 2 fs  Flexible mountain range display could probably do all these measurements !! (testing in SPS) (AB-RF, AB-CO support - OASIS) Transverse plane – via ADT PUs and signal processing

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 10 RF System -Additional Functionality – Stage 2 on (1) Machine Protection – Commitments and Issues - 1 (AB-RF AB/CO-MP) Connection of ACS SC cavities He levels & pressure to Beam Permit Estimate 0.3 deg/hour at 500uA (J. Tuckmantel) With safe beam defined as 3.5 mA at 450 GeV => 15 deg/hr.! Measure ΔT once beam circulating – Define safe beam/special MP input (AB-RF-CS, AB-CO/MP) Beam quality SPS LHC: SPS extraction veto, and LHC beam quality measurements - discussions ongoing, criteria, methods (AB-RF, AB-CO/MP) ‘Seamless retry’ on next batch - studies ongoing - timing considerations ! (AB-CO timing) On-line frequency measurement: Dedicated instrument… Dynamically: using variant of trigger unit to measure - say to 20 Hz in 50ms (AB-RF) ADT Limit external input above safe beam level – signal processing or direct inputs ? (AB-RF)

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 11 RF System -Additional Functionality – Stage 2 on (2) Machine Protection – Commitments and Issues - 2 (AB-RF/CS AB/CO-MP) Abort Gap monitoring: Monitoring with SRT (AB-BDI) RF methods? – studies & SPS tests done – Chamonix XII, E. Shaposhnikova et al. Gated BCT : is it worth trying ? ISSUES – SRT at 450 GeV, RF methods: sensitivity at high energy Abort Gap cleaning: Transverse excitation with damper - Successful SPS tests See E. Shaposhnikova Chamonix XII – to follow up soon with BT (B. Goddard) RF Failures to Beam Permit Klystron trip above half nominal? Stable below this for 1 RF trip – (T. Linnecar Chamonix XIV) Hardware outputs made to interlock system ADT signal processing to discuss – hardware inputs will be made

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 12 RF System - Additional functionality – Stage 2 on (3) ACS Feedback and beam control Longitudinal damper – perhaps not available till end 2007 ! => need good energy matching and injection phase setting 1-turn feedback - available – needed above half nominal. Systems will need commissioning with the various beams Transverse Damper Will definitely need for nominal, But at what level? Studies ongoing. Will depend on impedance ! (AB-RF, AB-ABP) Again will need commissioning with the various beams

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 13 RF System - Additional functionality – Stage 2 on (4) Longitudinal Emittance Blow-up To keep constant transverse instability threshold during ramp (impedance threshold decreases rapidly with energy – needed for what bunch intensity?) Relatively easy to do in RF hardware… (AB-RF) Will need beam commissioning RF issues Equipment Damage on Power Transients (Not below half-nominal) Power limiting solutions Performance consequences (Studies ongoing. J.Tuckmantel, SM18 experience) (AB-RF) Noise and lifetime measurements very important ! (klystron ripple etc.)

LHC Performance Workshop – Chamonix XV January 2006 E. Ciapala - RF Commitments and Major Issues 14 Conclusions Hardware Commissioning Time scales, resources etc – tight - for LLRF and SC cavities ! Readiness for first beam Good state if the UX45 & SR4 commissioning do go according to plans Initial beam measurements important ! Higher intensities Major part of functionality already in place for pilot Beam control – Longitudinal feedback later Machine protection issues, abort gap monitoring and cleaning Synchronization and safe injection! Beam commissioning - Need time at each new stage of beam operation ! RF commissioning team will study details… Commitments to other systems Responsibilities well defined…