RF Commitments and Major Issues

1. 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 23-27 January 2006

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; 1010 to 9 1010( 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 E. Ciapala - RF Commitments and Major Issues

3. Review of RF Equipment – (1) • Commitment – provide operational acceleration, TD and wideband PU systems ! Major part of RF equipment needs to be in place for Hardware Commissioning and be made operational by the end E. Ciapala - RF Commitments and Major Issues

4. UX45/RUX 45 installation • Aug 2005 • Integration Layout • Jan 2006 E. Ciapala - RF Commitments and Major Issues

5. Review of RF Equipment – (2) 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) 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 ..) 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) 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 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) 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 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 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.) 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… E. Ciapala - RF Commitments and Major Issues