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Status of the ERL Project in Japan

Status of the ERL Project in Japan. Norio Nakamura for the ERL Collaboration Team. Institute for Solid State Physics(ISSP), University of Tokyo . ERL collaboration team. High Energy Accelerator Research Organization (KEK)

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Status of the ERL Project in Japan

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  1. Status of the ERL Project in Japan Norio Nakamura for the ERL Collaboration Team Institute for Solid State Physics(ISSP), University of Tokyo

  2. ERL collaboration team High Energy Accelerator Research Organization (KEK) M. Akemoto, T. Aoto, D. Arakawa, S. Asaoka, A. Enomoto, S. Fukuda, K. Furukawa, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, T. Honma, T. Honma, K. Hosoyama, M. Isawa, E. Kako, T. Kasuga, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, T. Matsumoto, H. Matsushita, S. Michizono, T. Mitsuhashi, T. Miura, T. Miyajima, H. Miyauchi, S. Nagahashi, H. Nakai, H. Nakajima, E. Nakamura, K. Nakanishi, K. Nakao, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, S. Ohsawa, T. Ozaki, C. Pak, H. Sakai, S. Sakanaka, H. Sasaki, Y. Sato, K. Satoh, M. Satoh, T. Shidara, M. Shimada, T. Shioya, T. Shishido, T. Suwada, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, S. Yamamoto, Y. Yano, M. Yoshida Japan Atomic Energy Agency (JAEA) R. Hajima, R. Nagai, N. Nishimori, M. Sawamura Institute for Solid State Physics (ISSP), University of TokyoN. Nakamura, I Itoh, H. Kudoh, T. Shibuya, K. Shinoe, H. Takaki UVSOR, Institute for Molecular Science M. Katoh, M. Adachi Hiroshima University M. Kuriki, H. Iijima, S. Matsuba Nagoya University Y. Takeda, T. Nakanishi, M. Kuwahara, T. Ujihara, M. Okumi National Institute of Advanced Industrial Science and Technology (AIST) D. Yoshitomi, K. Torizuka JASRI/SPring-8 H. Hanaki

  3. Outline • Overview of the ERL project • R&D status- Gun and SC cavities • Compact ERL- Design study and building • Summary

  4. ERL Project Parameters of the 5-GeV ERL KEK site 5GeV ERL Parameters of the light sources Compact ERL (cERL)

  5. Compatibility of ERL and XFEL-O (a) 5-GeV ERL 2-loop ERL XFEL-O (b) 7.5-GeV XFEL-O Orbit Bump Section SC cavities Possible scheme for compatibility of 2-loop ERL and XFEL-O 2-loop ERL XFEL-O Bunch train and pulsed bump for hybrid operation • SC cavities shared by introducing an orbit bump of a half RF wavelength • 5-GeV ERL beam 2 times accelerated with the orbit bump off • 7.5-GeV XFEL-O beam 3 times accelerated with the orbit bump on

  6. 500-kV DC Photocathode Gun guard ring against field emission 500-kV gun with a segmented insulator HV terminal field emission support rod guard ring ceramic gun chamber cathode anode e-beam Segmented insulator with guard rings employed to mitigate field emission. segmented insulator

  7. HV Testing of 500-kV DC Gun 500 kV for 8 hours without any discharge Field distribution of the 500-kV gun 1200 HV terminal 1000 segmented insulator current through resistors 800 height (mm) 600 radiation level is within the background. no clear evidence for dark current. 400 6.8 MV/m on guard rings 8.3 MV/m on support rod 200 gun chamber 14.3 MV/m on nose of support rod 0 (HV testing done without a cathode electrode) -200 0 200 400 600 R. Nagai et al., to be published in Rev. Sci. Instr. radius (mm) Talk by N. Nishimori for more details.

  8. Test Injector Beamline • Test injector beamline set up in the PF-AR-south building. • Purposes : • To gain operation experience of the low energy beam. • To evaluate performance of the guns by measuring the emittance and bunch length with a diagnostic line. • To develop the 2nd 500-kV gun and the injector line used at cERL. Laser system 4th solenoid 3rd solenoid 2nd slit (horizontal) 1st slit (horizontal) 2nd solenoid 2nd slit (vertical) 1st solenoid 1st slit (vertical) 200 kV gun Beam Dump 2nd 500 kV gun test area Test beamline 5th view screen buncher Laser room 1st view screen 4th view screen 3rd view screen 2nd view screen deflector Bending magnet 200kV Gun 2nd 500kV Gun test area The same layout as cERL injector Beam diagnostic line(emittance & bunch length measurements) Beam dump line Talk by T. Miyajima for more details.

  9. Drive Laser System Laser system for gun commissioning at KEK • 1.3 GHz, 515 nm, 20 ps, 1.5 W (10mA operation) • Yb fiber laser oscillator (Cornell type) + fiber amplifier • Second harmonic generation (SHG): 100mW output achieved • Construction of pulse shaping system and transport to the gun • Ti:sapphire psec laser for high-charge and short bunch tests • 1.3 GHz, 800nm(tunable), 20 ps, 15 W (100mA operation) • Yb fiber laser oscillators (EO modulation & linear cavity types) • 10W + 200W fiber amplifiers • SHG and OPA for tunable wavelength around 800 nm Development of system components by AIST and ISSP Yb fiber laser system at KEK oscillator 10W amplifier Ti:sapphire laser system at KEK Yb fiber oscillator and amplifier developed by AIST and ISSP

  10. Injector SC Cavities (1) HOM couplers Two input ports ・ Three 2-cell cavities for 5 – 10 MeV acceleration of 100 mA beam ・ Accelerating field : 15 MV/m ・ Two input couplers for each cavity ・ Four or five HOM couplers (loop and antenna types) for each cavity Prototype 2-cell cavity K. Watanabe, S. Noguchi, E. Kako et al., Proc. of SRF09, Berlin, 2009. Design of HOM couplers Basic cavity Parameters for Injector

  11. Injector SC Cavities (2) without pick-up probes of HOM couplers 30MV/m 44 MV/m Heat-up of HOM probe 1st vertical test (2009 Apr.) 2nd vertical test (2010 Feb.) Set-up for a vertical test • Vertical test results of 1st prototype cavity • Maximum accelerating field : 30 MV/m • ( 44 MV/m without HOM probes) • Heating of HOM probes for high fields • Stable operation for 11 hours at 15-16 MV/m 11-hour operation @15-16MV/m Lack of Liq. He

  12. Injector SC Cavities (3) SC Cavity 300-kW klystron • Two Input couplers tested in early 2010 • 300-kW klystron successfully developed • (S. Fukuda et al., 6th Conf. of Particle Acc. Society of Japan, 2009) • 2nd prototype cavity with 5 HOM couplers fabricated. • Three real cavities under fabrication • Design of cryomodule almost completed 2nd prototype cavity with 5 HOM couplers Input coupler Cryomodule Water Cooling Target 200 kW CW Warm Window 300 K 80 K Zo = 41.5 W 5 K Two input couplers for High Power Test

  13. Main SC Cavities (1) Parameters of main SC cavity • Target and feature of main SC cavity • Acceleraitng field: 15 MV/m (f=1.3GHz) • Beam current : 100 (acc.) + 100 (dec.) = 200 mA • HOM damping design • Large-aperture iris and beam pipe and HOM absorber • Eccentric-fluted beam pipe • (converter from quadrupole to dipole mode) HOM absorber Eccentric-fluted beam pipe HOM absorber 9-cell cavity design E-single C-single E-single C-single Two type of single-cell cavities Vertical test Eacc > 20 MV/m achieved for both cavities

  14. Main SC Cavities (2) X-ray mapping by a rotating mapping system Angle[deg] Broad X-ray signal 0 180 360 1cell 2cell 9-cell cavity 3cell 4cell 1011 2K 5cell 6cell 1010 7cell Q0 4.2K 8cell 109 8-9 iris (150 °) 9cell Vertical test 108 30 0 5 10 15 20 25 Eacc [MV/m] Array of PIN diodes • Maximum accelerating field：15-17 MV/m • Accelerating field limited by field emission • A tip found on an iris between 8th and 9th cells •  Vertical test resumed after polishing the tip Sharp X-ray signal Tip on an iris of the cavity (f : several hudred mm) K. Umemori, T. Furuya et al., SRF09.

  15. Main SC Cavities (3) Cryomodule • Ceramic windows and bellows of an input coupler fabricated and tested  Ceramic window design slightly modified. • HOM damper prototype with a comb-type RF shield fabricated and HOM absorbers tested. • Cryomodule design containing two cavities with three HOM dampers in progress. HOM dampers Cavities Input couplers HOM damper Input coupler Prototype HOM damper without absorber Left: outside Right: inside Cold window Bellows Warm window Cooling air Warm window Cold window RF power H. Sakai et al., SRF09. M. Sawamura et al., SRF09.

  16. Compact ERL Compact ERL Before constructing a large-scale ERL facility, we need to demonstrate the expected ERL performance using key components. Parameters of the Compact ERL East Counter Hall Conceptual Design Report published in 2007 KEK Report 2007-7/JAEA-Research 2008-032 R. Hajima, N. Nakamura, S. Sakanaka, Y. Kobayashi eds. 100 m

  17. Injector design for cERL • Parameters optimization • Generic algorithm • Tracking code GPT • Space charge effects included • No CSR in merger • Optimization result • Rectangular type gives smaller emittance than the sector type. • Normalized emittance 0.4 – 0.5 mm mrad for 2 – 3 ps bunch length. • Injector components of cERL • Photocathode DC gun • Two solenoids • Bunching cavity (Buncher) • Three SC cavities • Five quadrupole magnets • Merger (using three bending magnets) • Initial Conditions • Electron distribution on cathode: beer-can shape • Initial charge: 80 pC (1) Sector type (bending angles：-19, 22, -19degree) Normalized rms emittance 0.4 ～ 0.5 mm mrad (2) Rectangular type (bending angles：-16, 16, -16degree)

  18. Error Analysis of cERL Injector Amplitude error in RF cavity Phase error in RF cavity Summary of error analysis results An example of error analysis results (Arrival time offset vs RF amplitude error) Gun ripple < 0.1 %, RF amplitude error < 0.1 %, RF phase error < 0.1 ° Talk by T. Miyajima for more details.

  19. Optics Design of 1-loop cERL Chicane Long straight section 1st TBA arc 2nd TBA arc Beams Extractor Merger Beam dump Main SC cavities Gun Injector Compact ERL(1-loop model) Basic parameters • High current mode: 100 mA, 1 mm mrad • Low emittance mode: 10 mA, 0.1 mm mrad • Emittance almost preserved • CSR effects included Optics functions (in high-current and low-emittance modes) T. Shiraga, N. Nakamura et al., PAC09

  20. Bunch Compression in cERL st =56 fs (3) (4) Long straight section Chicane 1st arc (R56>0) 2nd arc (R56<0) Beams Extractor Merger Dump Gun Main SC Cavities injector (2) (6) (5) (1) Initial condition: st=1 ps Q=77 pC en=1 mm mrad 6 mec Momentum 12 ps time only b, x,y opt. sx,y opt. y-position 5 cm 5 cm x-position • Bunch compression and decompression successfully simulated. • Optics also optimized for avoiding serious beam loss after decceleration.

  21. Error Effects of Main SC Cavities DV/V -0.5%  +0.5% DY=0mm st=56 fs DY=±1mm st=267 fs 1st arc 2nd arc Orbit distortion and emittance growth due to +1-mm horizontal alignment error of 8 main SC cavities in low-emittance mode and their correction DfRF +1.0°  -1.0° Bunch profile at exit of the 1st arc with ±1-mm vertical alignment error of 8 main SC cavities in bunch compression Bunch length and arrival time variations at exit of the 1st arc due to RF amplitude and phase errors in bunch compression • Bunch length and arrival time variations due to RF amplitude and phase errors •  0.01 % amplitude and 0.01 deg phase control required for bunch compression • Orbit distortion, emittance growth and bunch lengthening due to alignment error of SC cavities •  Orbit correction using eigenvector method with constraints(EVC) successfully applied

  22. Optics Design of 2-loop cERL Adjustment chicane Merger Beam dump Branch chicane Main superconductor cavities DC gun Extractor Layout of 2-loop cERL (tentative) Optics of 2-loop cERL (tentative) M. Shimada et al., ERL09. Optics design of 2-loop cERL in progress

  23. cERL Building Jan. 2010 Feb. 2009 The hall is being cleaned. Liq. He refrigerator is being installed. East Counter Hall Reconstruction of the East Counter Hall for the compact ERL

  24. Plan View of the Compact ERL (1) SCC vertical test area Magnet power supplies RF sources Liq. He refrigerator system Laser hut Compact ERL Electronics hut SCC R&D area Vacuum hut Final version of the compact ERL(2-loop, 100mA, 245 MeV)

  25. Plan View of the Compact ERL (2) SCC vertical test area Magnet power supplies RF sources Liq. He refrigerator system Laser hut Compact ERL Electronics hut SCC R&D area Vacuum hut Commissioning will start with a minimum version (1-loop, 10mA, 35 MeV) in FY2012.

  26. Summary ERL Project • Compact ERL (final version : 2 loop, 245 MeV, 100 mA) • Two-loop 5-GeV ERL and 7.5-GeV XFEL-O R&D in progress • 500-kV DC photocathode gun and injector beamline • Drive laser system for the gun • SC cavities for both injector and main linacs Compact ERL (cERL) • Design and error analysis of injector and 1-loop cERL studied • Optics of a 2-loop cERL under design • East Counter Hall at KEK renewed as cERL building • Commissioning (35MeV, 10mA, 1 loop) planned in FY2012

  27. Thank you for your attention!

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