2. Status of the RF System 09/03/2016 AWAKE RF Status2 D. Barrientos, T. Bohl, A. Butterworth, H. Damerau, W. Höfle, T. Levens, J. Molendijk, S. Rey, U. Wehrle (CERN) J. Moody, P. Muggli (MPP)

3. Outline Overview of AWAKE synchronization and RF distribution Commercial Equipment AWAKE SPS Fibre Link Stabilization for SPS synchronization Main RF Divider Fractional Divider Status & Outlook 09/03/2016 AWAKE RF Status3

4. Overview of AWAKE synchronization and RF distribution Laser PLL Fibre link stabilization 6 GHz master GPS receiver Fibre receiver/trans mitter SPS synchro crate 88.2 MHz (divider) 5995.8 MHz (M.O.) 10 MHz (reference) 9.97 Hz, 8.68 kHz, 400.8 MHz, 10 MHz Fractional divider SPS Main RF divider 400.8 MHz Fast pulse triggers Buffer amplifiers Electron LLRF Various frequencies distributed (many!) Fast pulse triggers (~20 adjustable) Laser Buffer amplifiers Fast pulse triggers 176.3 MHz Timing 200.4 MHz Proton LLRF Extraction and bunch rotation triggers BA4/building 871 TSG40 BA3/Faraday Cage 2997.9 MHz Commercial Equipment Existing RF Designs to be built New RF Design Menlo Systems Trimble

5. Commercial Equipment - GPS Receiver Thunderbolt E GPS Disciplined Clock 10 MHz reference and GPS Antenna - Received CERN GPS Antenna cable from: bldg. 871 roof, to GPS rack - Installed Fibre from GPS rack to TSG40 - Installed Rack Enclosure Thunderbolt - to be built Copper to Fibre interface adapter - to be built (based on existing interface EDA-03329) 09/03/2016 AWAKE RF Status5 Images from : http://trl.trimble.com/docushare/dsweb/Get/Document-383329/022542-010B_Thunderbolt-E_DS_0807.pdf CERN Contribution

6. Commercial Equipment – Master Oscillator and Components for LASER Synchronization BOM-PD (Balanced Optical Microwave Phase Detector) Synchronization Box Master Oscillator 5995.798136 MHz Four SMA outlets 10..13 dBm < 20 fs jitter [10 Hz..10 MHz] <100 fs jitter [1 Hz.. 10 MHz] Photo Detector for 88 MHz: For synchronization verification Photo Detector for 5995 MHz detection For out of loop tests 09/03/2016 AWAKE RF Status6 Green: Acquired in 2015 Blue: Ordering now Delivery expected 1 st week June at the latest. M.O. in 5-8 weeks. MPP Contribution

7. AWAKE - SPS Fibre Link Stabilization for SPS Synchronization SPS beams must be delivered at AWAKE in synchronism with the AWAKE e - RF system and the laser pulse rate. Via 3 km fibre optic links SPS RF (BA 3) receives: RF reference frequency (~400 MHz) Common frequency F c between AWAKE RF and SPS RF (f rev SPS / 5 ~ 9 kHz) Laser repetition rate (~10 Hz) At flat top SPS RF executes: «Coarse» re-phasing (< SPS T RF )using F c «Fine» re-phasing (down to 10 ps) RF reference frequency received from AWAKE specified to be stable within <= 1 ps, to be fully transparent for AWAKE Extraction pulse generation synchronized with Laser rep-rate The critical RF reference frequency transmission requires a stabilized fibre link. 09/03/2016 AWAKE RF Status7 BA3 AWAKE ~ 3 km

8. AWAKE SPS Fibre Link Stabilization - Drift Measurements A series of measurements were made during 2015, using a Vector Voltmeter VME module* to evaluate the typical phase drift of a fibre link round trip from the SPS faraday cage to AWAKE and back. Total fibre length = 6288 m Issues both with the temperature recording and the phase detector range caused some periods to be blank. 09/03/2016 AWAKE RF Status8 T °C t * EDA-02557 using AD8364 (mag) and AD8302 (phase) Φ deg @200MHz ~277.8 ps/div

9. AWAKE SPS Fibre Link Stabilization - Drift Measurements 09/03/2016 AWAKE RF Status9

10. AWAKE SPS Fibre Link Stabilization 09/03/2016 AWAKE RF Status10 EDA-03276

11. AWAKE SPS Fibre Link Stabilization 09/03/2016 AWAKE RF Status11 Three Prototypes EDA-03276-V1 received Feb. 15 th All Signal paths, ADC & DAC operational (no hardware design bugs) Tests ongoing Firmware development ongoing Preliminary result phase detector noise floor <1 ps.

12. Main RF Divider 09/03/2016 AWAKE RF Status12 5995.8 MHz (reference) 88.17 MHz 9.97 Hz 8.68 kHz 2997.9 MHz 176.34 MHz 44.08 MHz 88.17 MHz From Laser

13. Main RF Divider 09/03/2016 AWAKE RF Status13 5995.8 MHz (M.O.) 88.17 MHz from Laser 2997.9 MHz 176.34 MHz 88.17 MHz 44.08 MHz 8.68 kHz 9.97 Hz Fract. Divider Reset 176.34 MHz 88.17 MHz To Fract. Div To Fibre Link Stabilizer Design nearly ready for PCB / module production

14. Fractional RF Divider 09/03/2016 AWAKE RF Status14 Currently a LEP fractional divider module is being modified by S. Rey, with an external VCO module to generate the 400 MHz reference (from 176MHz). This interim solution will allow for SPS beam commissioning (AWAKE phase 1) before a high quality design can be developed and produced. The VCO used for the interim solution may serve as the base of the final design. Divider Module LEP VCO module Analog Devices http://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/EVAL-ADF4118.html

15. ItemStatus Rack infrastructure, network, RF cabling and fibres, crates Available GPS antenna, receiver for 10 MHz Completion of installation in 04/2016 6 GHz master RF oscillatorPurchasing via MPP, delivery expected 04/2016 Laser synchronizationPartly ordered from supplier, expected 06/2016 Main dividerPrototype hardware expected for 04/2016, but needs firm- and software, prototype must work Fractional divider, ratio 25/11Temporary modified modules from LEP with reduced signal quality, expected 04/2016 Compensated optical linkPrototype being tested, needs firm- and software Reproduction of existing and test hardware: ~80 modules of about 10 different types Potential delays with clock generator and hardware for precision triggers (mainly for beam diagnostics) including some firmware Status and Outlook

16. All major electronics developments launched Pace and manpower insufficient to complete hardware by mid 2016, limited availability of specialists during commissioning LLRF for 3 GHz electron beam not started due to lack of manpower Dual 3 km test link setup

17. Thank You for your Attention 09/03/2016 AWAKE RF Status17

18. Backup Slides 09/03/2016 AWAKE RF Status18

19. Index of Backup Materials 09/03/2016 AWAKE RF Status19 Fibre Link Phase Drift Compensation – Component Selection Fibre Link Phase Drift Compensation – Simplified Concept Fibre Link Phase Drift Compensation – Using X-OR Fibre Link Phase Drift Compensation – Final Setup Fibre Link Phase Drift Compensation – Calibration Fibre Link Phase Drift Compensation – Design Details Fibre Link Phase Drift Compensation – Critical Path Fibre Link Phase Drift Compensation – ADC Driver AWAKE Experimental Program

20. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status20 MC100EP196 limitations are: Random jitter performance 3 ps Non linear analogue fine delay Non monotonic non linear steps ON Semiconductor® D. Valuch CERN BE/RF MC100EP195 step delay measurements using Agilent E5071C on SPS Damper Loops module EDA-02917

21. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status21 Test results FTLF1321P1BTL (Finisar) Signal quality measurement using SSA E5052B Keysight comparing the Phase Noise of: E4428C Agilent (red) Same but through SFP test fixture (green & black) Green VME power- supply Black E3620A HP ext. supply From 10Hz to 100MHz J SFP ~ 400 fs -100 dB -120 dB -140 dB 1Hz1kHz 1MHz

22. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status22 Test results FTLF1321P1BTL (Finisar) Signal quality measurement using SSA E5052B Keysight comparing the Phase Noise of: E4428C Agilent @ 400MHz (background) SFP connected to fibre test system. Transceiver powered by ext. E3620A HP supply From 1Hz to 100kHz J SFP+FF+FR ~ 190 fs 1Hz100Hz 10kHz -120 dB -100 dB -60 dB 10Hz1kHz100kHz Signal quality measurement done through 2 x 3 km fibre test system with an optical splitter midway. -140 dB

23. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status23 X-OR Phase Discriminator Good sensitivity -> PECL about 800 mV/180° 640 µV/ps @ 400 MHz X-OR gate MC100EP08 was retained due to: Typical jitter 0.2 ps (max <1 ps) Fully differential LVPECL operation > 3 GHz rated Low cost

24. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status24

25. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status25 Main Critical Components are: Programmable Delay Lines Fine granular sub ps resolution. Course range 10 ns Part to part reproducibility (tracking) Phase Discriminator Good sensitivity Copper to Optical Interfaces Good availability Common Characteristics Low Jitter (< 1 ps) Using noise immune differential signalling

26. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status26 Programmable Delay Lines Criterion Fine granular sub ps resolution. Part to part reproducibility (tracking) SY100EP196 (MICREL) was retained due to: Analogue fine tune-able 0-30 ps + digital 10 ps steps 10 ns range (10 bit) Typical RMS jitter 0.2 ps (max <1 ps) Linearity +/-10%LSB (~ +/-1ps) > 3GHz rated MC100EP196 (ON Semiconductor) was NOT selected: Typical RMS jitter 3 ps Poor Linearity MICREL®

27. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status27 Copper to Optical Interface Profit from newer low-cost technologies Previous Experience: LLRF LHC uses older pig-tail TX / RX STX-24-PST-B & SRX-24-PST-B (OCP) SONET OC-24 Max raw Bit-rate 1.3 Gbps Mfgr. Spec. RMS Jitter 0.005 UI = ~3.8 ps Much better with stable clocks vs data! Implement generic SFP cage equipped with for example: Low cost: FTLF1321P1BTL (Finisar) SONET OC-48 λ = 1310 nm (mono-mode fibre) Max raw Bit-rate = 2.67 Gbps Mfgr. Spec. RMS Jitter 0.007 UI = ~2.6 ps Much better with stable clock operation Measured TX+RX 10Hz to 100MHz J SFP ~ 400 fs

28. Fibre Link Phase Drift Compensation – Component Selection 09/03/2016 AWAKE RF Status28 Signal quality measurement test setup: 2 x 3 km fibre with an optical splitter midway. FTLF1321P1BTL TX RX

29. Fibre Link Phase Drift Compensation – Simplified Concept 09/03/2016 AWAKE RF Status29 Ideal Procedure Regulate both analogue fine delays of Tdf and Tdr to keep  = 0 Once the fine delay gets close to the limit Insert a course delay step on the concerned delay (outside of SPS cycle) Let the regulation loop restore  = 0

30. Fibre Link Phase Drift Compensation – Simplified Concept 09/03/2016 AWAKE RF Status30

31. Fibre Link Phase Drift Compensation – Using X-OR 09/03/2016 AWAKE RF Status31 Valid approach if delay controls have perfect delay tracking. Imperfections will cause drift when course stepping one delay line (end of analogue control range) How to calibrate Tdf = Tdr? Or worse Tdf = Tdr + Offset? (when Tff ≠ Tfr small delta) X-OR

32. Fibre Link Phase Drift Compensation – Final Setup 09/03/2016 AWAKE RF Status32 Add one delay line to create 90° phase shift in one branch T 90° Added circuits to enable calibration. 1:4 Fanout Buffer, NB6L14 (3 GHz) 2 x 2 Crossbars, NBSG72A (>7 GHz) Both devices member of the new ON Semiconductor series

33. Fibre Link Phase Drift Compensation – Calibration 1/3 09/03/2016 AWAKE RF Status33 Phase 1: Calibrate T 90° Set T 90° Delay to a reasonable value Connect phase detector to T 90° Delay driven from reference source only Search for E = 0 by varying T 90°

34. Fibre Link Phase Drift Compensation – Calibration 2/3 09/03/2016 AWAKE RF Status34 Phase 2: Equalise Delay lines T df = T dr Connect phase detector to the reference source via T df, T dr & T 90° Search for E = 0 by varying either of Delay lines T df or T dr

35. Fibre Link Phase Drift Compensation – Calibration 3/3 09/03/2016 AWAKE RF Status35 Phase 3: Beam based calibration Using Operational Connections Both phase 1 & 2 introduce small errors due to device output skew (5 ps typ) Additionally we may have Tff ≠ Tfr Add a small delay offset to one Tdf or Tdr delay to remove residual drift.

36. Fibre Link Phase Drift Compensation – Design Details 09/03/2016 AWAKE RF Status36 Circuits in critical path have separate linear regulated supplies: V CCA (+3.3V source) V TTA (+1.3V sink for LVPECL terminators) Use complementary X-OR outputs representing +E and -E Common references for both ADC driver level shifters ADC drivers optimal dynamic range 2.5V/180° => ~0.019 ps / LSB (16 bit ADC and RF@400MHz) Subtraction of the Digital +E with -E eliminates LVPECL and reference offsets / drifts in both branches LPF out [V]ADC-P [V]ADC-N [V] 2.32.50 1.91.25 1.502.5 LPF AD7903 Dual Diff 16 bit ADC

37. Fibre Link Phase Drift Compensation – Critical Path 09/03/2016 AWAKE RF Status37 cm

38. Fibre Link Phase Drift Compensation – ADC Driver 09/03/2016 AWAKE RF Status38 U1 + U2 = ADA4941-1 Analog Devices 18 bit ADC Driver

39. AWAKE Experimental Program Phase 1: Understand the physics of self modulation instability processes in plasma. Phase 2: Probe the accelerating wakefields with externally injected electrons. 09/03/2016 AWAKE RF Status39 laser pulse proton bunch gas plasma Laser dump SPS protons 10m SMI Proton beam dump Laser Proton diagnostics BTV,OTR, CTR p Plasma cell  Rb vapour source Proton beam  drives the plasma wakefield + undergoes self-modulation instability.  LHC-type proton beam, 400 GeV/c, 3E11 protons/bunch,,  = 400 ps long Laser beam:  ionizes the plasma + seeds the self-modulation instability of the proton beam.  4.5 TW laser, 100 fs

40. AWAKE Experimental Program Phase 1: Understand the physics of self modulation instability processes in plasma. Phase 2: Probe the accelerating wakefields with externally injected electrons. 09/03/2016 AWAKE RF Status40 Laser dump e-e- SPS protons 10m SMI Acceleration Proton beam dump RF gun Laser p Proton diagnostics BTV,OTR, CTR e - spectrometer Plasma cell  Rb vapour source Proton beam  drives the plasma wakefield + undergoes self-modulation instability.  LHC-type proton beam, 400 GeV/c, 3E11 protons/bunch,  = 400 ps long Laser beam:  ionizes the plasma + seeds the self-modulation instability of the proton beam.  4.5 TW laser, 100 fs Diagnostics  BTVs, OTR, CTR Electron source and beam  Witness beam to ‘surf’ on the wakefield and get accelerated  16 MeV/c, 1.2 E9 electrons/ bunch,  = 4ps long Electron spectrometer system