WIR SCHAFFEN WISSEN – HEUTE FÜR MORGEN Steps towards beam commissioning: Low Level RF system group Thomas Schilcher :: Paul Scherrer Institut SwissFEL Commissioning Workshop, 21 March 2016 FHNW Campus Brugg-Windisch

Low Level RF System / Interlock System Page 2 LLRF: set amplitude (power) & phase of individual RF stations (goal: set physical quantities) monitors/archives amplitudes (power) & phase along the RF path with full rep. rate of 100 Hz (averages, waveforms) provides statistical information about RF stability runs local RF feedback loops to stabilize amplitude/phase with respect to reference signal act as actors in a global beam based feedback system (later stage) supports the operators in setting up an RF station (Operating Point Determination, State Machines) Interlock System: protect RF station and its equipment from physical damage guide the operator to trace down faults of the system

control system (incl. cavity temp. control) main interfaces Interfaces / Dependance Page 3

Controls:  Standard controls infrastructure (alh, software deployment, archiver, auto save&restore, snapshots,...)  beam synchronous data acquisition (independent from RF repetition rate)  simultaneous retrieval of synchronous/asynchronous data  super-periods for the events, pulse-ID  reliable operating system / drivers / gateways / data buffer /... RF:  tightly coupled installation / commissioning sequence Interfaces / Dependance RF installations, HV mod. assembly / diode mode LLRF electronics installation / calibration / system integration cable calibration ILK test RF conditioning LLRF optimization ready for beam cabling AIE RF LLRF ~1 week <1 week tunnel open closed

Hardware installation / System commissioning in OSFA before beam Page 5 summary: - LLRF inst./comm. tasks are contained in above schedule - LLRF can in principle meet this schedule - strongly depending on Section RF / AIE RF system installation/commissioning schedule (according to M. Pedrozzi, 18-MAR-2016 ) ? ! ?

handover to operation team: fully conditioned RF stations power calibrated read-backs fully integrated into EPICS (PVs for operation already defined) expert GUIs partly automated procedures (e.g. Operating Point Determination) running local RF feedbacks Handover to operation, pre-beam checks Page 6 not included * : RF timing beam phase calibration optimum structure temp. gradient calibration operator GUIs beam based feedbacks full RF system automation virtual RF stations *refers mainly to injector commissioning

System commissioning with beam Page 7 Priority (till 12/2016) Dedicated Beam Time Req. Time system optimization (optimum timing, optimum structure temperatures, optimum RF pulse shaping,...) highyes~2 shifts per RF stat. problem solving (especially of running systems) highpossibly... beam loading studies highyes~4-6 shifts automation tests / Virtual RF Stations negotiableyes/noTBD (also depends on availability of OBLA test stand) stability measurement program (jitter, correlations, optimization of RF feedback loops,...) mediumyesTBD drift studies lowpossiblyTBD

What makes us confident and happy Page 8 injector: LLRF hardware mostly installed or characterized in lab basic functionality tested at C-band test stand (OBLA) reliable planning from electricians

What makes us worry Page 9 unrealistic project planning in connection with strong coupling to other subsystems (no reserve) unknown EMI problems which we may encounter insufficient tests with new concepts (data buffer streaming) insufficient commissioning time of LLRF systems due to many other high priority commissioning tasks in the project insufficient testing time for further developments which are relevant for linac commissioning (Virtual RF stations, automation, beam loading studies,...)

What we also wanted to mention… Page 10 same controls test infrastructure outside SwissFEL network desirable (data buffer, archiver,...) short term RF stability (<1s) fully depending on RF drive chain – will not improve unless major sub-systems will be upgraded (e.g. installing new modulators in injector)