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Linac Coherent Light Source (LCLS) Low Level RF System Injector Turn-on December February 8, 2006
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Safety First and Second and Third…..to Infinity
Hazards in the LLRF system RF 1kW at 120Hz at 5uS = 0.6 Watts average, 2 Watt average amps at 2856MHz, 60W average amps at 476MHz Hazards – RF Burns Mitigation – Avoid contact with center conductor of energized connectors. All employees working with LLRF systems are required to have the proper training. 110VAC Connector Hazards - Shock Mitigation - Don’t touch conductors when plugging into outlet. All chassis are inspected by UL trained inspector.
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Scope of Work – Injector Turn-on
Linac Sector 0 RF Upgrade WBS All 3 RF Chassis completed and Installed Control Module to be installed Feb 06 Sector 20 RF distribution system WBS Phase and Amplitude Controllers – 9 units Phase and Amplitude Monitors – 2 dual channel units Phased Locked Oscillator LO Generator Multiplier – 476MHz to 2856MHz – 2 units Amplifiers – 4 units Laser Phase Measurement LLRF Control and Monitor System WBS 1 kW Solid State S-Band Amplifiers – 5 units Phase and Amplitude Monitors – 16 dual chan units Phase and Amplitude Controllers – 6 single chan units Bunch Length Monitor Interface Beam Phase Cavity WBS Will use single channel of RF Monitor Chassis Pill box cavity with 2 probes and 4 tuners 52 Chassis Total 9 Chassis Completed
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LCLS Layout P. Emma
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LLRF Control system spans Sector 20 off axis injector to beyond Sector 30
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LCLS RF Jitter Tolerance Budget
Lowest Noise Floor Requirement 0.5deg X-Band = 125fS Structure Fill time = 100nS Noise floor = 11GHz 10MHz BW 476MHz X-band X- 0.50 RMS tolerance budget for <12% rms peak-current jitter or <0.1% rms final e− energy jitter. All tolerances are rms levels and the voltage and phase tolerances per klystron for L2 and L3 are Nk larger, assuming uncorrelated errors, where Nk is the number of klystrons per linac. P. Emma
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Slow Drift Tolerance Limits
(Top 4 rows for De/e < 5%, bottom 4 limited by feedback dynamic range) Gun-Laser Timing 2.4* deg-S Bunch Charge 3.2 % Gun RF Phase 2.3 Gun Relative Voltage 0.6 L0,1,X,2,3 RF Phase (approx.) 5 L0,1,X,2,3 RF Voltage (approx.) (Tolerances are peak values, not rms) P. Emma, J, Wu * for synchronization, this tolerance might be set to 1 ps (without arrival-time measurement)
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Linac Sector 0 RF Upgrade
LCLS must be compatible with the existing linac operation including PEP timing shifts Master Oscillator is located 1.3 miles from LCLS Injector 1.3 Miles to LCLS Injector Measurements on January 20, 2006 show 30fS rms jitter in a bandwidth from 10Hz to 10MHz PEP PHASE SHIFT ON MAIN DRIVE LINE MDL RF with TIMING Pulse – Sync to DR
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Linac Sector 0 RF Upgrade Status
New Low Noise Master Oscillator – Done New Low Noise PEP Phase Shifter RF Chassis – Done Control Chassis – Feb 06 New Low Noise Master Amplifier – Done Main Drive Line Coupler in Sector 21 – Done Measurements Noise floor on 476MHz of -156dBc/Hz Integrated jitter from 10Hz to 10MHz of 30fS
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Sector 20 RF Distribution
Phase Critical Cables Laser <140ft < 700fSpp Gun < 100ft < 400fSpp
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Sector 20 RF Distribution System Status
Phase Locked Oscillator – 476MHz Preliminary Design – same as SPPS Low Noise 119MHz VCO and Multipliers in house Analog Track/Hold / feedback amp complete unit tested at SPPS May consider digital feedback amp if time permits LO Generator – MHz Preliminary Design complete – 80% of Parts are in house PC Board in design Multipliers - 476MHz to 2856MHz – Done Phase and Amplitude Control Unit In Design – Testing IQ modulators and amplifiers – See Next Section Phase and Amplitude Monitor Unit In Design – Testing Mixers, Amplifiers, Filters – See Next Section Amplifiers – not ordered yet Laser Phase Measurement System – Design Started
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Distributed Control System
LLRF Control System Distributed Control System Microcontroller based IOC Control and Monitor Modules Central Feedback Computer See LLRF Control talk Control breakout session – Attached By Dayle Kotturi
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LLRF Control and Monitor System Status
1 kW Solid State S-Band Amplifiers – 5 units 1kW amplifier modules currently in test Existing amplifier support design under review Phase and Amplitude Monitors – 16 dual chan units Preliminary Design Complete Evaluating amplifiers, mixers, and filters Phase and Amplitude Controllers – 6 single chan units Preliminary design complete Evaluating mixers and amplifiers Bunch Length Monitor Interface Need Specifications
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Beam Phase Cavity Status
Measurement of beam phase to RF reference phase. The result will be used to correct timing of laser to RF reference. Cavity is located between L0A and L0B. Electronics will use single channel of RF Monitor Chassis Pill box cavity with 2 probes and 4 tuners Cavity Electronics will use single channel of RF Monitor Cavity in design - probe and tuner design complete Fab, Test, Tune – May 2006 Bake – June 2006
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Status Summary Linac New Low Noise Source – RF components installed, Controls Feb06 RF Distribution – Prototyping underway (R. Akre, B.Hong, H. Schwarz) Monitor Controller Board (J. Gold, R. Akre, Till Straumann) Single channel prototype for ADS5500 tested to specifications Four channel ADS5500 board – layout complete (SNR 70dBFS) Switched to LTC bit 130MSPS ADC (Prototype in test) (SNR 77dBFS) RF Monitor Board in preliminary design (H. Schwarz, B.Hong) Testing mixers Control Boards (J. Olsen) Fast Control Board – in test Slow control board – May use fast board RF Control Board in preliminary design (H. Schwarz, B. Hong) Software (D. Kotturi, Till Straumann) EPICS on RTEMS on Microcontroller done Drivers Algorithms System Completion - December 2006 for Injector
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End of LLRF RF Talk Backup for RF Talk
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MPS – PPS Issues Addressed by Controls Group Not Reviewed Here
Vacuum New vacuum system summary to be fed to each klystron existing MKSU. PPS System Injector modulators will be interlocked by Injector PPS system. PPS requirements for radiation from the injector transverse accelerator needs to be determined. Radiation levels will be measured during testing in the Klystron Test Lab – Feb 06.
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Bandwidth of S-Band System
Upper Frequency Limit – 10MHz Beam-RF interaction BW due to structure fill time < 1.5MHz S-Band Accelerators and Gun ~10MHz X-Band and S-Band T Cav Structure RF Bandwidth ~ 16MHz 5045 Klystron ~ 10MHz Lower Frequency Limit – 10kHz Fill time of SLED Cavity = 3.5uS about 100kHz Laser – Needs to be measured ~ 10kHz
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Noise Levels RF Reference Single Side Band (SSB) Noise Floor
2856MHz RF Distribution -144dBc/Hz 119MHz (24x = +28dB +2 for multiplier) 2830.5MHz Local Oscillator -138dBc/Hz Integrated Noise -138dBc/Hz at 10MHz = -65dBc = 32fS rms SNR = 65dB for phase noise Added noise from MIXER (LO noise same as RF) SNR of 62dB ADC noise levels SNR of 70dB – 14bit ADS5500 at 102MSPS
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Phase Noise – Linac Sector 0
OLD MASTER OSCILLATOR -133dBc/Hz at 476MHz 340fSrms jitter in 10MHz BW NEW MASTER OSCILLATOR -153dBc/Hz at 476 MHz 34fSrms jitter in 10MHz BW Integrated Noise - Timing Jitter fs rms Integral end 5MHz kHz Integral start 1M 100k 10k 1k Aug 17, 2004 Sector Jan 20, 2006 Sector
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Sector 20 RF Distribution Cable Errors
Temperature Coefficient of 2.8ppm/ºF and Cable length is 1200ºS/ft All Cables except LASER are less than 100ft Distances feet and errors in degrees S total range RF Hut Down Linac Wall Injector Total Unit Ft degS ft degS ft degS ft degS ft degS DegS Laser Gun L0-A B Phas L0-B L0-T L1-S L1-X Temperature Variations: RF Hut ±1ºF : Penetration ±0.1ºF : Linac : ±0.2ºF Shield Wall ±0.1ºF : Injector ±1ºF
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RF Control and Monitor Signal Counts
Distribution (5~2850MHz, 4<500MHz) 9 IQ Mod 4 RF monitors RF Gun 1 Klystron 7 RF monitors Beam Phase Cavity 1 IQ mod 2 RF monitor L0-A Accelerator 1 Klystron 4 RF monitors L0-B Accelerator 1 Klystron 4 RF monitors L0-T Transverse Accelerator 1 Klystron 4 RF monitors L1-S Station 21-1 B, C, and D accelerators 1 Klystron 6 RF monitors L1-X X-Band accelerator X-Band 2 IQ Mod 5 RF monitors S25-Tcav 1 Klystron 4 RF monitors S24-1, 2, & 3 Feedback 3 Klystrons S29 and S30 Feedback 2 IQ modulators 476MHz Total modulators and monitors 23 modulators 40 monitors Totals at ~2856MHz 15 modulators 33 monitors
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LLRF Control and Monitor System
1 kW Solid State S-Band Amplifiers – 5 units Phase and Amplitude Monitors – 16 dual chan units Phase and Amplitude Controllers – 6 single chan units Bunch Length Monitor Interface – Need Specifications
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RF Control Required 11 Units Includes Distribution
RF Control Module consist of the following: Input Coupler, IQ Modulator, Amplifier, Output Coupler Filters for I and Q inputs
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RF Monitor Required 16 Chassis for Injector – Includes Distribution
LO MHz : RF 2856MHz IF 25.5MHz (8.5MHz x 3 in sync with timing fiducial) Double-Balanced Mixer Mixer IF to Amp and then Low Pass Filter Filter output to ADC sampling at 102MSPS 2830.5MHz Local Osc. To ADC LTC2208 SNR = 77dBFS 102MSPS 2856MHz RF Signal
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1 kW Solid State S-Band Amplifiers
Electrical Design Complete – Under Review Mechanical design in progress Modules in house – in test Support parts – Some parts in house Power Supplies, relays, chassis need to be ordered
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SLAC Linac RF – New Control
The new control system will tie in to the IPA Chassis with 1kW of drive power available. Reference will be from the existing phase reference line or the injector new RF reference I and Q will be controlled with a 16bit DAC running at 119MHz. Waveforms to the DAC will be set in an FPGA through a microcontroller running EPICS on RTEMS. Existing System
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Controls Talk
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Outline LLRF Controls Requirements External Interfaces Schedule Design
Date Needed Prototype Completion Date Hardware Order Date Installation Test Period Design Design Maturity (what reviews have been had) State of Wiring Information State of Prototype
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At 120 Hz, meet phase/amp noise levels defined as:
Requirements At 120 Hz, meet phase/amp noise levels defined as: 0.1% rms amplitude 100 fs rms in S-band (fill time = 850 ns) 125 fs rms in X-band (fill time = 100 ns) All tolerances are rms levels and the voltage and phase tolerances per klystron for L2 and L3 are Nk larger, assuming uncorrelated errors, where Nk is the number of klystrons per linac (L2 has 28; L3 has 48)
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Engineering Requirements
When beam is present, control will be done by beam-based longitudinal feedback (except for T-cavs); when beam is absent, control will be done by local phase and amplitude controller (PAC) Adhere to LCLS Controls Group standards: RTEMS, EPICS, Channel Access protocol Ref: Why RTEMS? Study of open source real-time OS Begin RF processing of high-powered structures May 20, 2006
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LLRF to LCLS global control system
External Interfaces LLRF to LCLS global control system PVs available for edm screens, archiving, etc over controls network LLRF VME to beam-based longitudinal feedback from feedback: phase and amplitude corrections at 120 Hz over private ethernet from LLRF: phase and amplitude values (internal) LLRF VME to LLRF microcontrollers from VME: triggers, corrected phase and amplitude from microcontrollers: phase and amplitude averaged values at 120 Hz, raw phase and amplitude values for debug
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External Interfaces: Laser - Tcav
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External Interfaces: L2-L3
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Date Needed: injector: Dec/06 Prototype Completion Date:
Schedule – for PAD Date Needed: injector: Dec/06 Prototype Completion Date: Mar/06: board prototype (2 or 4 chan, thermo) May/06: final board. Test (incl temp. cycling) Hardware Order Date: continuous Hardware Delivery Date: by Sep/06: chassis (15 dual channel) avail. Installation: injector: Oct/06 Test Period: injector: Nov/06
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Date Needed: injector: Dec/06 Prototype Completion Date:
Schedule – for PAC Date Needed: injector: Dec/06 Prototype Completion Date: Jan/06: first board prototype Mar/06: first board prototype if not same as fast PAC Hardware Order Date: continuous Hardware Delivery Date: by Sep/06: chassis (6 single channel) Installation: injector: Nov/06 Test Period: injector: Nov/06
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Date Needed: injector: Dec/06 Prototype Completion Date:
Schedule – for slow PAC Date Needed: injector: Dec/06 Prototype Completion Date: Mar/06: first board prototype if different than fast PAC Hardware Order Date: continuous Hardware Delivery Date: by Sep/06: chassis (6 single channel) Installation: injector: Nov/06 Test Period: injector: Nov/06
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Schedule – for timing/feedback crate
Date Needed: injector: Dec/06 Prototype Completion Date: Fall/06 Hardware Order Date: done Hardware Delivery Date: have it Installation: injector: Nov/06 Test Period: injector: Nov/06
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Design Design maturity (what reviews have been had): RF/Timing Design, DOE Review, August 11, 2004 Akre_FAC_Oct04_RF_Timing, FAC Review, October, 2004 Low Level RF Controls Design, LCLS Week, January 25-27, 2005 Low Level RF, Lehman Review, May 10-12, 2005 LLRF Plans for Development and Testing of Controls, LCLS Week, July 21, 2005 Low Level RF Design, Presentation for Controls Group, Sept. 13, 2005 LLRF Preliminary Design review, SLAC, September 26, 2005 LCLS LLRF Control System - Kotturi, LLRF Workshop, CERN, October 10-13, 2005 LCLS LLRF System - Hong, LLRF Workshop, CERN, October 10-13, 2005 LLRF and Beam-based Longitudinal Feedback Readiness - Kotturi/Akre, LCLS Week, SLAC, October 24-26, 2005 LCLS Week LLRF and feedback - Kotturi/Allison, LCLS Week, SLAC, October 24-26, 2005 LLRF, LCLS System Concept Review/Preliminary Design Review, SLAC, November 16-17, 2005 Comments LLRF Beam Phase Cavity Preliminary Design review, SLAC, November 30, 2005 Docs at: State of wiring: percent complete Captar input will be given at time of presentation State of prototype: PAD (1 chan ADC) and PAC boards built (shown on next pages).Testing.
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PAD – the monitor board
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PAD – the monitor board
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PAC – the control board
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PAC – the control board
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Additional Slides The following two pages show an overview of the LLRF control modules. From these diagrams, counts of module types, as well as function and location are seen.
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Overview of LLRF at Sector 20
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Overview of LLRF at Sector 24
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