12.4: SRF HOM Diagnostics: Experimental Results and Future Plans Nicoleta Baboi*, Liangliang Shi*# *DESY; #UMAN for the HOM-team EuCARD2 WP12 Meeting 16 April 2014, Saclay

Aim HOM-based beam diagnostics for the European XFEL (E-XFEL) Beam phase (wrt RF) and position In 3.9 GHz and 1.3 GHz cavities Strong interconnection to the FLASH linac Benefits Reduction in emittance dilution from transverse wakefields by centering beam in accelerating cavities Direct, on-line measurement of beam phase wrt RF phase Additional beam position monitoring

Contents Introduction HOM-based beam position monitoring Principle The European XFEL and FLASH Overview of HOM-based diagnostics HOM-based beam position monitoring for 1.3GHz cavities for 3.9GHz cavities HOM-based beam phase monitoring [for 3.9GHz cavities] Partial summary Stability study → Liangliang Shi

Principle Filter higher dipole mode for beam position Filter higher monopole mode for beam phase × Beam offset [mm] Phase difference

The European XFEL accelerating structures experimental hall undulators http://www.xfel.eu/

FLASH

Accelerating Cavities for the E-XFEL and FLASH The 1st dipole band HOMBPM The 2nd dipole band The 1st dipole band Coupled cavities

Status and Plans for HOM-based Beam Position Monitoring (HOM-BPM) FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi’s talk) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea…

Status and Plans for HOM-based Beam Phase Monitoring FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration (phase or even frequency drifts?) started stability studies (L. Shi) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea…

Status and Plans for HOM-BPM / 1.3 GHz cavities / FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY; 2006) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi’s talk) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH Past experience / Achieved past year / Under work / EuCARD-2 challenges

Status and Plans for HOM-BPM / 1.3 GHz cavities / E-XFEL FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY; 2006) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi’s talk) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH Past experience / Achieved past year / Under work / EuCARD-2 challenges

HOM-BPM / 1.3 GHz cavities / E-XFEL: Electronics Designed and Tested in Lab Single channel: Direct sampling of all three frequencies without any downconversion mTCA standard RTM side AMC side Samer Bou-Habib, WUT, DESY

HOM-BPM / 1.3 GHz cavities / E-XFEL: Electronics Designed and Tested in Lab (2) System architecture 8 channels Samer Bou-Habib, WUT, DESY RTM side AMC side DRTM-HOM DAMC-DS800 RF1 .. RF8 REF (RF-backplane) REF FP 6 8 CLK +Distribution CLK out

HOM-BPM / 1.3 GHz cavities / E-XFEL: Electronics Designed and Tested in Lab (3) Filter test board two filters, one on each side each for 3 frequencies (1.3/1.7/2.4) Example measurement Attenuation settings: -8dB @1.3 GHz, -16db @ 1.7 GHz, -24dB @dB The filter should be tuned and then implemented in an 8 channel RTM RF1 .. RF8 REF (RF-backplane) REF FP 6 8 CLK +Distribution CLK out DRTM-HOM

Status and Plans for HOM-BPM / 3.9 GHz cavities / FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) Will add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea… Past experience / Achieved past year / Under work / EuCARD-2 challenges

HOM-BPM / 3.9 GHz cavities / FLASH: Electronics from FNAL Installed Nathan Eddy, FNAL Bandpass Filter ~5.43 GHz or 9.06 GHz 100 MHz BW Mixer uTCA Digitizer SIS8300 (108MS/sec) LO 30 MHz IF

HOM-BPM / 3.9 GHz cavities / FLASH: 5GHz Downconverter and PLL Boards Nathan Eddy, FNAL

HOM-BPM / 3.9 GHz cavities / FLASH: First Beam signals on scope 5 GHz (C1H2) 9 GHz (C1H1) Signals from 9 bunches

HOM-BPM / 3.9 GHz cavities / FLASH: Raw ADC Signals in DOOCS Each plot: signal from one HOM coupler Signals from 2 bunches

Status and Plans for HOM-BPM / 3.9 GHz cavities / E-XFEL FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea… Past experience / Achieved past year / Under work / EuCARD-2 challenges

Bandpass Filter ~5.43 GHz or 9.06 GHz 100 MHz BW HOM-BPM / 3.9 GHz cavities / E-XFEL: Design of 5 GHz Down-converter ready Bandpass Filter ~5.43 GHz or 9.06 GHz 100 MHz BW Mixer uTCA Digitizer SIS8300 (108MS/sec) LO 30 MHz IF Thomas Wamsat, DESY

HOM-BPM / 3.9 GHz cavities / E-XFEL: Design of 5 GHz PLL ready Thomas Wamsat, DESY Design of 9 GHz DCW and PLL under work

Status and Plans for HOM-PhMon / 1.3 GHz cavities FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration (phase or even frequency drifts?) started stability studies (L. Shi) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea… Past experience / Achieved past year / Under work / EuCARD-2 challenges

HOM-PhMon / 1.3 GHz cavities / E-XFEL: Electronics Designed and Tested in Lab Same as electronics as presented for HOM-BPM / 1.3GHz RTM side AMC side Samer Bou-Habib, WUT, DESY

Status and Plans for HOM-based Beam Phase Monitoring FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY) Raw signals used for beam centering EuCARD2: Unstable calibration (phase or even frequency drifts?) started stability studies (L. Shi) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) To add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (low priority in EuCARD2) Same as for FLASH It would be nice to have only one overview page (with previous); if you have an idea… Past experience / Achieved past year / Under work / EuCARD-2 challenges

1st Deliverable Approaching Report on the design of electronics for XFEL-HOM diagnostics (M18) Good progress: 1.3GHz cavities design ready tests to be made with beam 3.9GHz cavities Design for 5GHz channels ready 1st boards should be ready in May and then tested in lab Design of 9GHz channels will follow

Summary of Part 1 HOM-based BPMs HOM-based phase monitoring for 1.3GHz cavities: prev. experience with electronics at FLASH Design of electronics for the XFEL finished -> 1st milestone Next: Tests with beam for 3.9GHz cavities FNAL electronics installed at FLASH E-XFEL electronics: design in advanced stage -> 1st milestone Next: Tests in lab and with beam HOM-based phase monitoring for 1.3GHz cavities Not for 3.9GHz cavities Part 2: Stability study → Liangliang Shi

Part 2: Liangliang Shi FLASH E-XFEL 1.3 GHz Cavities Electronics installed in 40 cavities (SLAC/CEA/DESY; 2006) Raw signals used for beam centering EuCARD2: Unstable calibration started stability studies (L. Shi’s talk) Electronics designed and tested in lab, based on same frequency as for FLASH (WUT/DESY) Next to be tested with beam 3.9 GHz Cavities Theoretical and experimental studies (EuCARD + FNAL) Defined specs for HOM-BPM electronics (also for E-XFEL) Electronics built by FNAL, installed (Mar. 2014); to be tested with beam; serves as prototype for E-XFEL EuCARD2: Unstable calibration (same problem as for 1.3 GHz?) Will add to stability study for 1.3 Electronics under design, based on same frequency ranges as for FLASH (DESY) But much more challenging: 8 coupled cavities cf. 4 4.5 cf 1 MHz bunch frequency Different orientation of cavities EuCARD2: Need significant theoretical and experimental studies (next talks) FLASH E-XFEL 1.3 GHz Cavities Proof-Of-Principle made (SLAC/CEA/DESY) Tests for E-XFEL to be made in FLASH Electronics designed and tested in lab (same electronics as for E-XFEL HOM-BPM, WUT/DESY) To be tested in FLASH EuCARD2: experimental studies 3.9 GHz Cavities So far no isolated monopole mode identified, which could be used for phase monitoring Theoretical (and experimental) studies (lower priority in EuCARD2) Same as for FLASH Past experience / Achieved past year / Under work / EuCARD-2 challenges

Thank you!

Reserve Slides:

Subtask 10.5.1 Two Choices for HOMBPM Electronics Localized modes 9060 MHz Coupled modes 5437 MHz “Common position” of power minimum Integrated power RMS Error at Module Center Pei Zhang

Specs for Final Electronics for FLASH defined Based on EuCARD work, specs defined for HOMBPM electronics for FLASH The European XFEL More research necessary, since there will be 8 cavities in 3.9 GHz module (EuCARD2, incl. 1.3 GHz cavities) Position type Resolution # of channels Local position in the cavity ~ 50-100 μm 6 HOM couplers Global position over the module ~ 20-30 μm 2 HOM couplers Bandpass Filter ~5.43 GHz or 9.06 GHz 100 MHz BW Mixer uTCA Digitizer SIS8300 (108MS/sec) LO 30 MHz IF Brian Fellenz, Nathan Eddy, Fermilab

HOMSC12, Cockcroft Institute, Jun 26th, 2012 Challenges Dipole beam-pipe modes The 1st and 2nd dipole band The 5th dipole band Fundamental band Large R/Q’s Modes propagate Pei Zhang HOMSC12, Cockcroft Institute, Jun 26th, 2012 Page 33

Electronics for 3.9GHz/FLASH from FNAL: Design CAN BUS CONTROLLER BOARD CAN I/O 5 GHz PLL 9 GHz PLL BPF 9GHz DOWNCONVERTERS [30 MHz OUT] 5 GHz DOWNCONVERTERS [30MHz OUT] 5 GHz & 9GHz [30 MHz OUT] 81MHz INPUTS 9 GHz DC 5 GHz DC 4-WAY SPLITTER 8-WAY IN 1 IN 2 IN 3 IN 4 IN 5 IN 6 IN FOR PHASE MEASUREMENTS P. S. +15V +7V 9GHz 5GHz LO MON. OUT

5GHz Downconverter Board from FNAL ATTEN 5-Bits 0-31 dB 30MHz BPF BW: 15MHz 40MHz LPF -20 dB 36 dB GAIN +7V IF Mon. Output 30 MHz 14 dB RF Monitor -10 dB RF DET. 19 dB 18 dB LO INPUT MON I MON -2 dB GAIN CTRL

9GHz Downconverter Board from FNAL ATTEN 5-Bits 0-31 dB 30MHz BPF BW: 15MHz 40MHz LPF -6 dB 36 dB GAIN +7V IF Mon. Output 30 MHz 19 dB RF Monitor -20 dB -10 dB RF DET. 18 dB LO INPUT MON I MON

5GHz PLL Board from FNAL REF 81MHz BPF BW: 7MHz LOOP FILTER 3 dB +7V OUTPUT +8 dBm 15 dB 2-WAY SPLITTER Output 81.25 MHz SCK RSTB SDI SEN SDO CP RF HMC702LP6CE PLL HMC430LP4 VCO +15V 16dB TEST CONNECTOR