1/19/2006Frank Lenkszus Advanced Photon Source 1 ILC Timing Frank Lenkszus Controls Group Advanced Photon Source Argonne National Lab

1/19/2006Frank Lenkszus Advanced Photon Source 2 Timing Functions Master oscillator distribution (1.3 GHz) 5 Hz timing fiducial distribution Programmable triggers for field hardware Mechanism to synchronize software processing to timing events Time fiducials for synchronized timestamps for software and hardware events. Develop pulse ID number to identify pulses within the 1 millisecond pulse train –ID number will accompany data relating to individual pulses

1/19/2006Frank Lenkszus Advanced Photon Source 3 Key Parameters that Influence Timing Bunch Compressor Phase Tolerance 0.03 to 0.1 degrees at 1.3 GHz Inter-linac timing tolerance100 femto-seconds

1/19/2006Frank Lenkszus Advanced Photon Source 4 Timing Global Specifications Timing Phase locked to RF System –Stability at the point of RF measurement and control: ~10 picoseconds –Short Term Stability for Bunch Compressor: ~100 femtoseconds Timing phase reference will be distributed via active phase stabilized redundant fibers in star configuration to sectors –Fiber cable has temperature coefficient: ~10 ppm/  C Timing phase reference to be dual redundant with auto failover –Timing phase reference distribution will use active phase stabilization Phase shifter will be based on fiber in a temperature controlled oven Will build on prior work for NLC and TELSA Local distribution (~500 meters) will be via coax Active phase stabilization scheme Phase averaging scheme 5 Hz timing fiducial will be encoded on timing phase reference by momentary phase shift –Others have used Amplitude Modulation.

1/19/2006Frank Lenkszus Advanced Photon Source 5 Timing Global Specifications (Cont.) Required timing triggers and other frequencies will be developed locally at sector locations from the distributed phase reference Local timing triggers will be developed by counting down phase reference Graded approach to timing trigger generation –High precision: (pico-second) –Medium precision (nano-second) –Low precision (microsecond) (Event System)

1/19/2006Frank Lenkszus Advanced Photon Source 6 Prior Work On Phase Reference Distribution TELSA –“First Generation of Optical Fiber Phase Reference Distribution System for TESLA”, Krzysztof, C., et al, TELSA Report NLC –A High Stability, Low Noise RF Distribution System”, Frisch, J., et al, Proceedings of 2001 PAC, Chicago, pp 816 – 818 –“R&D for the ILC Phase/Timing Distribution System”, Frisch, J. 10/20/04 KEK –KEK (“RF Reference Distribtution Using Fibre-Optic Links for KEKB Accelerator”, Natio, T. et al, PAC2001)

1/19/2006Frank Lenkszus Advanced Photon Source 7 TELSA Reference Distribution Specifications Short Term Stability (phase noise) << 1 ps, (10 fs at XFEL) Short term stability (minutes) < 1 ps at RF frequency ( GHz) Long term stability (days) < 10 ps ( GHz) System Length: up to 15 km Distributed frequencies MHz (Tests done at1.3GHz) High Reliability

1/19/2006Frank Lenkszus Advanced Photon Source 8 TESLA Features Use 1550 nm DFB Laser –Temperature controlled to 25  C Use SMF-28 fiber (Corning) –Loss 4.4 dB for 20 km fiber Phase Shifter –5km fiber inside an oven with 30  C temperature range Compensates for phase changes induced by 10  C temperature change of 15 km link Digital PID controller –Only PI gains used Transmit 1.3 GHz reference

1/19/2006Frank Lenkszus Advanced Photon Source 9 TESLA

1/19/2006Frank Lenkszus Advanced Photon Source 10 TELSA System Performance Integrated system test had problems –Had to reduce PID P gain to make system stable Caused by phase shifter dead-time –Couldn’t run tests for more than hours because of software malfunction Stability –Short Term Stability 0.3 psec –Long Term Stability 2 psec

1/19/2006Frank Lenkszus Advanced Photon Source 11 NLC Requirements Transmission length : 15 km Noise 10 sec to 10 kHz: < 0.12 psec RMS Stability < 1 hour:+/- 1 psec Stability Long Term:+/- 5 psec Temperature Stability:< 2x10 -8 /  C

1/19/2006Frank Lenkszus Advanced Photon Source 12 NLC Prototype Features Use 1550 nm DFB Laser –Laser pulsed at 3125 Hz to avoid interference between forward and reflected power. Use SMF-28 Single-mode fiber 15 km long Phase Shifter –6km fiber inside an oven –Oven continuously cooled by TEC cooler and heated by a wire grid. Prototype operated at 375 MHz carrier RF signals mixed down to 25 kHz IF and digitized at 200 kHz. Phase measured digitally in PC. PID loop implemented in PC to drive phase shifter All RF components and optical components were mounted in a temperature controlled oven. Test output signal filtered with 100 Hz bandwidth VCXO phase locked loop to reduce broadband noise.

1/19/2006Frank Lenkszus Advanced Photon Source 13 NLC Test Setup

1/19/2006Frank Lenkszus Advanced Photon Source 14 NLC Prototype Performance System Phase stability: 10 femtosecond per degree C per kilometer Phase Noise 0.1Hz to 10 kHz: 0.25 psec RMS –Later report of ~0.1 psec Stability < 1 hour:+/ psec Stability Long Term (1 month) :+/- 2 psec –Later report of +/- 1 psec Temperature Stability:< /  C

1/19/2006Frank Lenkszus Advanced Photon Source 15 Variations KEK (“RF Reference Distribtution Using Fibre-Optic Links for KEKB Accelerator”, Natio, T. et al, PAC2001) –Used Phase Stabilized Optical Fiber (PSOF) : 0.4ppm/  C (-10 to 30  C) –Used WDM (1310 (Forward) and 1550 (Reflected) nm to avoid crosstalk Avoids RF chopping –Distributes 509MHz –Temperature stabilized phase shifter Electronically controlled varactor diodes –Phase stability: ~ 2 degrees for 4.8 km PSOF cable

1/19/2006Frank Lenkszus Advanced Photon Source 16 Active Phase Stabilized Link

1/19/2006Frank Lenkszus Advanced Photon Source 17 Redundant Reference Transmission with Failover

1/19/2006Frank Lenkszus Advanced Photon Source 18 Sector Timing Distribution

1/19/2006Frank Lenkszus Advanced Photon Source 19 Sector Timing Controller

1/19/2006Frank Lenkszus Advanced Photon Source 20 Other Frequencies Other generated frequencies will be sync’d to 5 Hz timing fiducial 3.25 MHzInjector (1/ GHz) –Reference: BCD2005 General Parameters: 308 ns Linac Bunch Interval. 6.5 MHzInjector (Low Q option) (1/ GHz) –Reference: BCD2005 General Parameters: 154 ns Linac Bunch Interval 500 MHzDR(5/ GHz) 46.3 kHzElectron (6 km) DR Revolution Clock(500MHz/Harmonic #) kHzPositron (12 km) DR Revolution Clock (500MHz/Harmonic #) 54 MHzMode Locked Lasers (1/ GHz)

1/19/2006Frank Lenkszus Advanced Photon Source 21 Event System Bit serial system sends event codes Synchronous to 5 Hz and sub harmonic of 1.3 GHz Possible events –Start of Bunch Train –5 Hz –MPS Trip –Pulse Tic –Revolution Clock(s) (DRs) –GPS Clock Tick Event Receivers –Generate interrupt to processors to synchronize software processing –Time stamp counter –Low grade timing triggers on occurrence of specified events

1/19/2006Frank Lenkszus Advanced Photon Source 22 Numerology Items that influence flexibility in bunch pattern choice –Ratio of ML to DR RF (1300/500 => 13/5) –DR Harmonic number –Linac bunch spacing (nominal 308 nsec => 3.24 MHz) References that explore the relationships. –“Basic Timing Requirements for TELSA”, Kriens, W. TELSA Report –“Some Timing Aspects for ILC”, Ehrlichmann, H, DESY, Presented at GDE Freascati, December 2005.

1/19/2006Frank Lenkszus Advanced Photon Source 23 Some Timing Issues Fiber oven phase shifters are large and consume significant power (~ 1kW/fiber) Chop RF frequency or not – Avoid Circulator cross-talk –NLC chopped at 3125 Hz –TELSA – cross talk constant so don’t worry about it –KEK used WDM (1300/1500 nm) Bunch Compressor –Required stability at the cavities not demonstrated when transmitted over long distances Local reference distribution –Active Phase Stabilization Can we assume temperature stable enough through ½ sector so phase stabilizer not required for each local node. –Phase Averaging Requires directional couplers at each drop point.

1/19/2006Frank Lenkszus Advanced Photon Source 24 Local (IntraSector Reference Distribution) Reference: Frish, J. “R+D for the ILC Phase/Timing Distribution System”, 10/20/04

1/19/2006Frank Lenkszus Advanced Photon Source 25 Timing Questions Under what conditions should timing cause an MPS trip –Unrecoverable phase distribution error Interfaces/Timing Requirements: –MPS –BDS Timing Requirements for Accelerator Components –Table Number, Range, Resolution, Accuracy, Stability, Jitter –Kickers –Bpms –Laser Wire –Etc Bunch Compressor –Most stringent timing requirement Master Oscillator Specification

1/19/2006Frank Lenkszus Advanced Photon Source 26 Work to be done on Phase Distribution Establish stability/phase noise budget –Master Oscillator –Long haul distribution Bunch Compressor All other –Local (Intra Sector distribution) Prototype phase stabilized link building on NLC/TELSA work Extend prototype to redundant configuration –Develop and test auto failover Investigate options to distribute phase reference to Bunch Compressors

1/19/2006Frank Lenkszus Advanced Photon Source 27 Timing Requirements Gather list of devices requiring timing Develop table DeviceQuantityRangeResolutionJitterStabilityAccuracy

1/19/2006Frank Lenkszus Advanced Photon Source 28 Results of 1/17/2006 FERMI ILC RF and Controls Meeting LLRF LO to be 52 MHz (1.3GHz/25) LLRF ADC sampling frequency MHz (1.3GHz/15) 2% loss in Luminosity is driving Bunch Compressor specs. Bunch compressor (BC) requires a separate rf spec(0.03 deg, 0.08%) Rest of the system: –(+/-)0.5% energy error – brick wall limit! –0.5 deg, 0.5% uncorrelated –0.1 deg, 0.03% correlated For MO/phase reference distribution/reconstruction and no beam (pilot bunch) spec is –+/- 0.5 degrees rms (1 over 15 km over “long” time scale Beam based feedback (from cavity) will be used to stabilize locally distributed phase reference to the beam. Fermilab ILC Beam Test Facility Spec: –Rf specs for three cryomodules (24 cavities) powered by a single Klystron: 0.5%, 0.5 degree rms long term –Timing distribution jitter: 1 ps rms

1/19/2006Frank Lenkszus Advanced Photon Source 29 References “First Generation of Optical Fiber Phase Reference Distribution System for TESLA”, Krzysztof, C., et al, TELSA Report “A High Stability, Low Noise RF Distribution System”, Frisch, J., et al, Proceedings of 2001 PAC, Chicago, pp 816 – 818 “R&D for the ILC Phase/Timing Distribution System”, Frisch, J. 10/20/04 Larsen, R. S., Technical Systems Configurations – Electrical Subsystem: Instrumentation – Timing, Rev. 1, March 23, 2001 “Basic Timing Requirements for TELSA”, Kriens, W. TELSA Report “Some Timing Aspects for ILC”, Ehrlichmann, H, DESY, Presented at GDE Freascati, December 2005.