Status of the ERL Project in Japan

Transcription

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 Tokyo N. 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 1. Overview of the ERL project 2. R&D status - Gun and SC cavities 3. Compact ERL - Design study and building 4. Summary

4 ERL Project KEK site Parameters of the 5-GeV ERL Parameter Beam energy 5 GeV 5GeV ERL Average current ma Normalized emittance mm mrad Energy spread (rms) (0.5-2) 10-4 Bunch length (rms) 1-3 ps (usual mode) ~ 100 fs (bunch compression) RF frequency 1.3 GHz Compact ERL (cerl) Parameters of the light sources Parameter Spectral range 30 ev - 30 kev Average brilliance from insertion devices Average flux ph/s/mm 2 /mrad 2 /0.1%bw > phs/s/0.1%bw Number of ID s 20-30

5 Compatibility of ERL and XFEL-O (a) 5-GeV ERL 2-loop ERL Orbit Bump Section SC cavities XFEL-O (b) 7.5-GeV XFEL-O Possible scheme for compatibility of 2-loop ERL and XFEL-O 2-loop ERL XFEL-O 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 Bunch train and pulsed bump for hybrid operation

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

7 HV Testing of 500-kV DC Gun Field distribution of the 500-kV gun 500 kv for 8 hours without any discharge height (mm) 8.3 MV/m on support rod segmented insulator 6.8 MV/m on guard rings gun chamber HV terminal current through resistors radiation level is within the background. no clear evidence for dark current MV/m on nose of support rod (HV testing done without a cathode electrode) radius (mm) R. Nagai et al., to be published in Rev. Sci. Instr. 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 2 nd 500-kV gun and the injector line used at cerl. Laser system Test beamline 1 st solenoid 2 nd solenoid 3 rd solenoid 4 th solenoid 2 nd slit 1 st slit (horizontal) (horizontal) 2 nd slit 1 st slit (vertical) (vertical) Beam Dump 200 kv gun 2 nd 500 kv gun test area buncher Laser room 1 st view screen 2 nd view screen The same layout as cerl injector 3 rd view screen 4 th view screen deflector Beam diagnostic line (emittance & bunch length measurements) 5 th view screen Bending magnet Beam dump line 200kV Gun 2 nd 500kV Gun test area 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 Development of system components by AIST and ISSP 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 Yb fiber laser system at KEK oscillator 10W amplifier Yb fiber oscillator and amplifier developed by AIST and ISSP Ti:sapphire laser system at KEK

10 Injector SC Cavities (1) 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 Basic cavity Parameters for Injector Two input ports HOM couplers Prototype 2-cell cavity K. Watanabe, S. Noguchi, E. Kako et al., Proc. of SRF09, Berlin, Design of HOM couplers

11 Injector SC Cavities (2) 30MV/m without pick-up probes of HOM couplers 44 MV/m Heat-up of HOM probe 1 st vertical test (2009 Apr.) 2 nd vertical test (2010 Feb.) Set-up for a vertical test Vertical test results of 1 st 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 MV/m 11-hour Lack of Liq. He

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

13 Main SC Cavities (1) Target and feature of main SC cavity 1) Acceleraitng field: 15 MV/m (f=1.3ghz) 2) Beam current : 100 (acc.) (dec.) = 200 ma 3) HOM damping design Large-aperture iris and beam pipe and HOM absorber Eccentric-fluted beam pipe (converter from quadrupole to dipole mode) Parameters of main SC cavity Frequency 1.3 GHz Iris diameter 80 mm Beam pipe diameter 100/120 mm R sh /Q 897 Ω E p /E acc 3.0 HOM absorber Eccentric-fluted beam pipe 9-cell cavity design HOM absorber E-single C-single C-single E-single Two type of single-cell cavities E acc > 20 MV/m achieved for both cavities Vertical test

14 60.0 Main SC Cavities (2) Q K 9-cell cavity 2K Vertical test E acc [MV/m] Maximum accelerating field:15-17 MV/m Accelerating field limited by field emission A tip found on an iris between 8 th and 9 th cells Vertical test resumed after polishing the tip X-ray mapping by a rotating mapping system Broad X-ray Angle[deg] signal cell 2cell 3cell 4cell 5cell 6cell 7cell 8cell 9cell 8-9 iris (150 ) Tip on an iris of the cavity (φ : several hudred µm) φ 337 φ 264 φ 235 φ 268 φ 400 φ 337 φ 264 φ 235 φ 268 φ 400 φ 337 φ 264 φ 235 φ 268 φ PI N1 PI N2 PI N9 PI N10 PI N11 PI N18 PI N19 PI N20 PI N27 PI N28 PI N29 PI N36 PI N37 PI N38 PI N45 PI N46 PI N47 PI N54 PI N55 PI N56 PI N63 PI N64 PI N65 PI N72 PI N73 PI N74 PI N81 PI N82 Array of PIN diodes Sharp X-ray signal K. Umemori, T. Furuya et al., SRF09.

15 Main SC Cavities (3) Cryomodule HOM dampers Cavities Input couplers 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. Input coupler HOM damper Bellows Warm window Cold window Prototype HOM damper without absorber Left: outside Right: inside Cold window H. Sakai et al., SRF09. Warm window Cooling air RF power M. Sawamura et al., SRF09.

16 Compact ERL Before constructing a large-scale ERL facility, we need to demonstrate the expected ERL performance using key components. Compact ERL Parameters of the Compact ERL Parameters Beam energy Injection energy Average current Acc. gradient (main linac) Normalized emittance Bunch length (rms) RF frequency MeV 5-10 MeV ma 15 MV/m mm mrad 1-3 ps (usual) ~ 100 fs (with B.C.) 1.3 GHz East Counter Hall Conceptual Design Report published in 2007 KEK Report /JAEA-Research R. Hajima, N. Nakamura, S. Sakanaka, Y. Kobayashi eds m

17 Injector design for cerl 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 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 mm mrad for 2 3 ps bunch length. (1) Sector type (bending angles:-19, 22, -19 degree) (2) Rectangular type (bending angles:-16, 16, -16 degree) Normalized rms emittance 0.4 ~ 0.5 mm mrad

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 1 st TBA arc 2nd TBA arc Beam dump Extractor Beams Merger Main SC cavities Compact ERL(1-loop model) Injector Gun Basic parameters Beam energy Beam current Normalized emittance ε n = ε/(γβ) 125 MeV ma 1 mm mrad (77 pc/bunch) 0.1 mm mrad (7.7 pc/bunch) Energy spread (rms) < Bunch length (rms) 1 3 ps (normal recirculation) ~ 100 fs (bunch compression) 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 σ t =56 fs (3) (4) (2) 1st arc (R 56 >0) Dump σ x,y opt. Chicane Extractor (6) Long straight section Beams Main SC Cavities Initial condition: σ t =1 ps Q=77 pc ε n =1 mm mrad only β, x,y opt. y-position Momentum Merger (1) injector 12 ps time 5 cm 6 m e c 5 cm 2nd arc (R 56 <0) Gun (5) Bunch compression and decompression successfully simulated. Optics also optimized for avoiding serious beam loss after decceleration. x-position

21 Error Effects of Main SC Cavities V/V -0.5% +0.5% 1 st arc 2 nd 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 φ RF Bunch length and arrival time variations at exit of the 1 st arc due to RF amplitude and phase errors in bunch compression DY=0mm σ t =56 fs DY=±1mm σ t =267 fs Bunch profile at exit of the 1 st arc with ±1- mm vertical alignment error of 8 main SC cavities 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 DC gun Main superconductor cavities Layout of 2-loop cerl (tentative) Extractor Optics design of 2-loop cerl in progress Optics of 2-loop cerl (tentative) M. Shimada et al., ERL09.

23 cerl Building Feb Jan 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) Magnet power supplies Liq. He refrigerator system SCC vertical test area RF sources Laser hut Electronics hut Compact ERL 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) Magnet power supplies Liq. He refrigerator system SCC vertical test area RF sources Laser hut Electronics hut Compact ERL 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!