Transcript RF - Indico
RF acceleration and transverse damper systems LHC Post Mortem Workshop, 17 Jan 2007 A. Butterworth AB/RF 1 Outline System & controls overview – 400MHz acceleration system (ACS) – Transverse damper (ADT) Data sources – Power systems – Low-Level systems LHC Post Mortem Workshop, 17 Jan 2007 – External diagnostics Triggering Remarks, status & conclusions 2 400 MHz main acceleration system (ACS) 2 LHC rings = 2 independent RF systems SC cavities (8 per ring) – 4 cryomodules of 4 cavities each RF power system: – One klystron amplifier per cavity – RF power distribution system (waveguides, circulators, loads) LHC Post Mortem Workshop, 17 Jan 2007 – industrial controls (PLC) Low Level system (fast RF controls): – cavity voltage and phase – beam phase and radial position – fast timing and beam synchronization – mostly digital, implemented in custom VME 3 RF Low-Level system layout (simplified) Surface building SR4 Beam Control beam 1 400MHz RF RF Voltage SUM RF Synchronization UX45 cavern Cavity Controller LHC Post Mortem Workshop, 17 Jan 2007 to SUM Beam Control beam 2 400MHz RF Cavity Controller Cavity Controller to SUM Kly Cavity Controller to SUM Kly Kly Antenna Antenna Cav to SUM Cav Kly Beam 1 Antenna Transverse Longitudinal (radial) (phase) pickup pickup Beam 2 Cav Cav Antenna Tunnel 4 Interlocks: RF interlock tree for one ACS RF line PLC Sum of Line 1 Level 1 Alarms Aux 24Vdc Module 1 Cavity HOM Wb A Emergency stop PLC Sum of HV Alarms HOM Nb A LHC Post Mortem Workshop, 17 Jan 2007 Timestamping (10us) VME module Circulator Water Flow Circulator Load Water Flow Modulator oil pump Sw Modulator Stab Sw Level 1 Ready Vacuum HOM Nb B Level 2 Ready Focus Circ load Water out Temp PLC Sum of RF Alarms Blower PLC Sum of Focus Ps Alarms Kly Window Air Out Temp Mains Kly Window Air Pressure Delay Klystron Drift tube temp Status Klystron HvBox Air Flow Klystron HvBox Air Temp PLC Sum of Line 1 Level 2 Alarms Module 2 Klystron Kly Coll Water in Temp Kly Coll Water out Temp Circulator Water out Temp HOM Wb B Sum of PLC Line 1 Alarms Klystron Body Water Flow Blower Sw Focus Ps CB Cooling TCU Watchdog Klystron Modulator Stab CB Services Water Leak Detector Cavity Kly Collector Water Flow Klystron switch MC Vac RF switch PLC Sum of Cooling Alarms Modulator oil Pump CB Kly Body Water out Temp Max Field Module 0 RF Intlk PLC Sum of Services Alarms Bunker water Ps Short circuit Heater Ps Open circuit DCCT PLC Sum of Filament Heater Alarms Module Kly Adet Jumper Circ Adet Level 2 Ready Jumper Load Adet MC Temp Mc Adet MC Blower Cathode Command status Jumper Wg Adet LowLevelLoops ? Modeanode Pre delay RF Enable Filament Hi Delay Filament Lo Status Jumper Jumper (reserved) Wattcher Hi Wattcher Lo Used for Beam dump Module 3 Module Level 1 Ready Bunker Water PLC Sum of DCCT Alarms Klystron Vac Gradator Access Cryo Vac He press L1 Cryo OK Cav Vac Radiation Spare1 Spare2 Hardware interlock crates (5us) read out via PLC Software interlocks in PLC (10ms) similar trees for HV and Beam interlocks 5 Transverse damper system (ADT) Feedback system using electrostatic kickers to damp – injection oscillations – coupled bunch instabilities beam Also excitation (measurements, abort gap cleaning) 16 electrostatic kickers – 4 per plane (H/V) per beam LHC Post Mortem Workshop, 17 Jan 2007 Power system: – amplifier chain with tetrode power amplifiers Kicker tanks – industrial controls (PLC) Low-Level signal processing – digital, custom VME Fast interlocks cf. ACS Tetrode power amplifiers 7.5 kV 6 Transverse damper system (ADT) Surface building SR4 Signal processing (FPGA) closed orbit suppression betatron phase adjust 1-turn delay + delay adjust UX45 cavern Hybrid 0° LHC Post Mortem Workshop, 17 Jan 2007 Driver amp D,S D,S 180° Driver amp Power amplifiers 0° 180° Driver amp Driver amp Power amplifiers Beam Pickup 2 Pickup 1 Kicker Kicker Tunnel 7 Data: Power system/PLC controls 20 PLCs for ACS 400 MHz acceleration system 8 PLCs for ADT Transverse Damper Supervision via FESA at 1 Hz – continuous values: powers, temperatures, pressures, flows • ~ 700 signals measurement system – statuses, faults, interlocks • ~ 150 signals measurement system LHC Post Mortem Workshop, 17 Jan 2007 Interlock state changes (leading to RF or HV trip or beam interlock) – Software interlocks timestamped to 10ms precision in PLC – Hardware interlocks timestamped to 10us precision in dedicated VME module – “first fault” memorized Interlock diagnostic performed in FESA alarm system 8 Data: Low level system embedded diagnostics Circular memory buffers incorporated in Low-Level VME boards – 3.2 ms @ 80 MS/s (36 turns) – 6 s @ 20 kS/s – sampling synchronous with RF – data tagged with revolution frequency clock LHC Post Mortem Workshop, 17 Jan 2007 • need correlation with UTC? total of ~ 256 MB for ACS system total of ~ 32 MB for ADT system 2 independent buffer sets: – Post Mortem – User (“Observation”) 9 Data: Stand-alone analogue acquisition Transverse damper schematic Fast analogue acquisition Surface building SR4 Signal processing (FPGA) – ADT: pickup and amplifier chain diagnostics closed orbit suppression betatron phase adjust 1-turn delay + delay adjust – cPCI fast digitizers, 8 bits at 80 MS/s UX45 cavern Hybrid 0° – sampling synchronous with RF LHC Post Mortem Workshop, 17 Jan 2007 – 64 channels with 10 MB each (1000 turns at 80 MS/s) – total of 640 MB 180° Driver amp D,S D,S Driver amp Power amplifiers 0° 180° Driver amp Driver amp Power amplifiers Beam Pickup 2 Pickup 1 Kicker Kicker Tunnel Low-frequency analogue acquisition (samplers) – ACS: detected RF power signals and He pressure – cPCI ADCs sampling at ~1 kHz – 98 channels, record length ~ few seconds – total of ~ 1 MB 10 RF frequency monitoring & beam diagnostics RF frequency monitoring and interlock (1 per ring) – VME Trigger Unit (VTU) used as 400MHz counter – updated at 20 Hz – used to generate beam interlock if outside limits – circular history buffer in FEC (few minutes) LHC Post Mortem Workshop, 17 Jan 2007 – ~ 50 kB APW wideband wall current monitor signal (1 per ring) – digitized at 8 GS/s, up to 170 turns – 256 MB could be made available for PM – bunch length & longitudinal emittance extracted at ~ 1 Hz – measurement system 11 Triggering The 2 rings are independent: separate buffers are used for Beam1 and Beam 2 PM timing event used to freeze: – fast (80 MS/s) stand-alone analogue acquisition – slow (1 KS/s/) analogue acquisition LHC Post Mortem Workshop, 17 Jan 2007 – RF frequency measurement (20 Hz) Many of the embedded PM buffers in the Low-Level VME boards have very short recording time (3 or 6 ms) – latency of PM event (< 2ms) may cause significant loss of data – BIS status signal distributed to all Low-Level VME crates and can be used to trigger buffer freezing – PM timing event used to initiate data upload and re-arm – In the case of dump without PM (e.g. inject and dump), re-arm after a few ms timeout 12 Remarks: Pre-processing and analysis Fast PM buffer data volumes: – embedded diagnostics ~ 300MB – stand-alone analogue signal diagnostics ~ 640MB – not clear how this can be reduced by pre-processing simple pre-analysis with extraction of gains, phases, signal levels etc. and their comparison with reference values might be possible in the Front-End more sophisticated analysis will require expert intervention LHC Post Mortem Workshop, 17 Jan 2007 – will not have such tools on day one simple signal visualization is a good starting point 13 Current status and conclusions PM buffers designed into the Low-Level equipment Additional buffers provided via stand-alone systems where needed Readout is an integral part of the FESA front-end software – Transmission of data to the PM system is still to be implemented Other data for correlation: – Slow data from power equipment will be acquired in Measurement and Logging systems LHC Post Mortem Workshop, 17 Jan 2007 – Interlocks will result in an accurately timestamped alarm in LASER Should a snapshot be added into the PM record? Concentrate initially on providing the necessary data, sophisticated analysis tools will come later 14