A free electron laser facility, SwissFEL, is under construction to aim at routine operation in 2017 by Paul Scherrer Institut (PSI). Mitsubishi Heavy Industries (MHI) has accepted order of one C-band waveguide network prototype (CWNP) for SwissFEL project in June 2014 and has been already delivered to PSI in December 2014. A C-band waveguide network connects the klystron to the four inputs of the accelerating structures. The CWNP has already installed in the test facility and high power test of it is planned by PSI. MHI also has accepted order of 26 C-band network series (CWNS) and the production of them have been started. We report the properties and the low-level RF test results for the CWNP.
Development of a superconducting RF electron gun (SRF gun) was started in KEK for the high-intensity electron gun which is required for the next generation ERL or a high power FEL system, in addition to the conventional DC electron gun. The preconditions of this SRF gun are 1.3 GHz of the resonant frequency, 100 mA of the beam current, and 2 MeV of the energy in the exit of gun. It was shown that low maximum surface electric field (42 MV/m), low emittance (1 mm mrad) and narrow energy spread (2 keV, 0.1 %) can be obtained by a simulation, and the manufacture situation was shown the last meeting. The manufactured cavity was named prototype #1 and electromagnetic evaluation and vertical test were performed. The result is separately reported by this meeting.
Here, the examining result of prototype #2 which added a high power RF coupler and the choke structure for cathode exchange is reported. It designed in consideration of the structure which attached two coaxial couplers in order to input 200 kW of RF power, the choke structure for making cathode exchange easy, and its manufacturability.
MHI has supplied the superconducting RF cavities and cryostats for electron accelerators. And Now MHI is developing the superconducting QWR cavity for heavy ion accelerator project at RIKEN in collaboration with RIKEN and KEK. For development of QWR cavity, MHI did the RF analysis in collaboration with KEK and did the forming examination of parts of QWR. This report provides the detail of activities for QWR development.
A high-intensity electron gun is required for the next generation ERL or a high power FEL system. KEK started development of a superconducting RF electron gun in addition to the conventional DC electron gun. 1.3 GHz of the resonant frequency, 100 mA of the beam current, and 2 MeV of the energy in the exit of gun are made into the precondition. By combining electromagnetic field analysis and charged particle dynamics analysis, the optimal design of the cavity shape, where the maximum surface electric field of less than 50 MV/m, a low emittance of less than 1 mm mrad, and a low energy spread of less than 0.1 % (2 keV)) can be filled with this precondition, was tried. The designed elliptical cavity is a 1.5-cell structure made of Nb material, and the three half cells are manufactured from one common die. Thermo-structural analysis under cryogenic temperature and vacuum environment was also carried out, and the resonance frequency change would be evaluated.
In April 2013, MITSUBISHI HEAVY INDUSTRIES, LTD. contracted with RIKEN to manufacture six C-band diskloaded type and constant gradient (CG) accelerating structures for XFEL facility SACLA (SPring-8 Angstrom Compact free electron LAser). These structures were newly designed for operation with an acceleration gradient of over 45 MeV/m and a repletion rate of 120 pps by RIKEN. We report the production and low-power RF properties of these accelerating structures.
MHI has supplied the superconducting RF cavities and cryostats for STF2 superconducting RF cryomodule at KEK. This report provides the detail of STF2 cryostat development.
MHI has so far manufactured 9-cell superconducting cavity for STF (Superconducting Test Facility), and ERL (Energy Recovery Linac) with KEK. MHI has developed the mass production construction method of superconducting cavity for ILC in parallel. This report provides status of development.
MHI is manufacturing the superconducting accelerating cavity module for the incidence unit and main accelerator in the cERL facilities constructed by the High Energy Accelerator Research Organization (KEK). Following are details on our work on the module.
Tohoku University had 300MeV linac and the 1.2GeV booster synchrotron for Electron Photon Science. The high energy part of the linac was broken by the 11 March 2011 off the Pacific coast of Tohoku Earthquake and restoration of the linac was difficult. Therefore, Mitsubishi Heavy Industries (MHI) supplied new 90MeV linac for booster synchrotron and completed the linac in January, 2013. It reports on production results of the linac.
MHI is developing both the cryomodule and superconducting accelerating cavity for the incidence unit and main accelerator at the cERL facilities constructed by the High Energy Accelerator Research Organization (KEK). Following are details on our work on the cryomodule and cavity.
In Pohang Accelerator Laboratory (PAL) in Korea construction of XFEL (X-ray Free electron Lazar) institution is under construction aiming at the completion in 2014. Energy 10GeV of the linac part of this institution and main frequency are planned in S-band (2,856 MHz), and about 178 S-band 3m accelerating structures are due to be used for this linac. The oscillation of an X-ray laser requires very low emittance electron beam. On the other hand, since the accelerating structure which accelerates an electron beam has a feed port of microwave (iris), the electromagnetic field asymmetry of the microwave feeding device called coupler worsens the emittance of an electron beam. MHI manufactured two kinds of S-band accelerating structures with which the electromagnetic field asymmetry of coupler cavity was compensated for PALXFEL linac. We report these accelerating structures.
Cavity fabrication method with new forming technology and Laser welding technology are reported. 1.3GHz 9-cell cavity with Laser welding technology for stiffener and flange joint is achieved 29 MV/m at vertical test at KEK and 1.3GHz 2-cell seamless dumbbell cavity are fabricated at MHI for verifying the fabrication method. These are reported in detail. Some other fabrication technology for cost reduction and stable quality are introduced.
XFEL/SPring-8 “SACLA”, designed for the 8 GeV beam energy and the under 0.06 nm shortest wavelength lasing, is now under commissioning to open it to the public in the end of fiscal year 2011. To radiate stable and brilliant XFEL, it is important to keep the high peak current of the electron beam after the bunch compression. A transverse RF deflector is used for diagnosing the longitudinal bunch structure. A required transverse voltage for SACLA is more than 40 MV. To achieve this requirement, we developed a C-band RF deflector, and we manufactured two 1.8m-long C-band RF deflectors. It was confirmed that the RF properties of manufactured deflectors were almost equivalent to the design values by the low-level RF measurements. Now the deflectors have installed in the SACLA, and contribute to commissioning.
An X-ray free electron laser (XFEL) is under construction in RIKEN/Spring-8. This facilities is planned to realize the X-ray laser in the spring of 2011. Mitsubishi Heavy Industries (MHI) began mass production of S-Band and C-band accelerating structures and SLED and waveguides from February 2007 for RIKEN X-FEL Project, and completed all components in March 2010. It reports on these mass production results and measurements results of accelerating structures.
A C-band rf pulse compressor stores the rf power from a klystron and generates a compressed rf pulse that has higher peak power in order to obtain a higher acceleration gradient. The XFEL project at Spring-8 uses 64 pulse compressor units. In December 2009, we completed the fabrication and RF measurement of these units. A high-power rf test was conducted in the test stand at RIKEN. The peak output power from pulse compressor is 260 MW, and the acceleration gradient of the accelerating structure is achieved to be 40 MV/m.
MHI has supplied 1.3GHz superconducting cavities for the Energy Recovery Linac (ERL) project and the International Linear Collider (ILC) R&D project (STF: Superconducting RF Test Facility in KEK) to KEK in Japan for several years.  We are improving the technology to design and fabricate the superconducting cavities for ILC R&D step by step. The status of superconducting cavity development for ILC at MHI is described in this paper.
Mitsubishi Heavy Industries developed C-band chork-mode type accelerating structures, and supplied four structures from 2002 to 2005 for RIKEN. These accelerating sections are operated with stability in accelerating gradient 37MV/m for SCSS test linac. We began mass production of 128 C-band accelerating structures from 2007 for RIKEN X-FEL Project, and completed 90 sections in July 2009. The RF aging is executed to several of these accelerating structures in RIKEN, and it was confirmed to drive in accelerating gradient 40MV/m without trouble. It reports on these accelerating sections mass production intermediate results.
C-band RF pulse compressor is a device that generates high peak RF-power by saving, and compressing the RFpower output from the klystron. XFEL project is scheduled to be installed 64 pulse compressor units, 2009 of August 49 units completed the fabrication and RF measurement. The pulse compressor is required for the high frequency stability, we improved the tuner structure for the frequency adjustment. As a result, the frequency became very stable, and high power test resulted of the test hall at RIKEN, the gain is obtained as designed. We will complete the production of The pulse compressor by the end of 2009.
MHI has supplied 1.3GHz superconducting cavities for the ERL (Energy Recovery Linac) project and the ILC R&D project (STF: Superconducting RF Test Facility in KEK) to KEK in Japan for the last few years. We are improving the technology to design and fabricate the superconducting cavities for ILC R&D step by step. We designed and fabricated nine STF-Baseline 9-cell cavities. We have improved the quality and productivity of the SRF activities for ILC. The status of superconducting cavity development for ILC at MHI is described in this paper.
XFEL/SPring-8 X-ray free electron laser is under construction at SPring-8 site. The construction period is scheduled 2006 to 2010, and the first X-ray beam is scheduled in 2011. This facility consists of 400 m long 8 GeV electron linear accelerator and 80 m long undulator line. In order to make the facility compact size, the C-band accelerator technology has been emplyed which enables accelerating beams at 35 MV/m. The RF acceleration cavities and associated waveguide components are under mass production at MHI (Mitsubishi Heavy Industry).
C-band RF compressor is a device that generates high peak RF-power by saving, and compressing the RF-power output from the klystron. In SCSS: The Spring-8 Compact SASE Source, Q-factor of C-band RF compressor is lower than theoretical figure. To improve Q-factor of C-band RF compressor, we changed the production method of C-band RF compressor from Electron Beam Welding (EBW) to the brazing in XFEL: X-ray Free Electron Lasers. As a result, Q-factor of C-band RF compressor has been improved, and it succeeded in the work improvement.
MHI has supplied superconducting cavities for the KEKB Crab project, ERL (Energy Recovery Linac) project and the ILC R&D (STF: Superconducting RF Test Facility in KEK) project to KEK in Japan for the last few years. We are improving the technology to design and fabricate the superconducting cavities for ILC R&D. We can present some examples of our work that have improved the quality and productivity of the superconducting cavities. We designed and fabricated four STF 1.0-type cavities and two STF 1.5-type cavities. The status of superconducting cavity development for ILC at MHI is described in this paper.
We report the developed result about the detuned S-band structure for X-FEL project of RIKEN (SPring-8). The main linear accelerators are the C-band(5,712MHz) structures. The S-band structures are used at the part of injector. The accelerating electric beams are single-bunch, but this project assume multi-bunch for increase of the average power in the future. Therefore we newly developed the detuned S-band structure considering the effect of the wakefield.
We developed and made the 476MHz booster cavity for SASE-FEL prototype accelerator of RIKEN (SPring-8). On this accelerator, the very low emittance electron beam made by electric gun (500keV) are bunched by the 238MHz prebuncher cavity. To transport this electron beam with low emittance kept, this 476MHz booster cavity grows the beam energy from 500keV to 1MeV. The main specifications of this cavity by low level RF test are following; frequency 476[MHz] (It is possible to fine-tuning by the tuners ), Q value 23343, coupler coupling 2.2, shunt impedance 3.674[MΩ]
We report on the result of Manufacturing four C-band Chork-Mode type accelerating structure for SASE-FEL test Linac of Riken. First accelerating structure was produced in MHI in 2002. This accelerating structure was supplied to the high gradient test, and the result that the RF input can be done with electric field 33MV/m on the axis, RF pulse width 1.2μs, and 30pps without trouble was obtained. This time, we produced three accelerating structures further. We report on the manufacturing and the finality low level RF examination result of these accelerating structures.
We report the developed result about the detuned S-band structure for X-FEL project of RIKEN We developed and made the238MHz Cavity for SPring-8 Compact SASE-FEL Source (SCSS) project. The electron gun using thermionic cathode makes a few μsec pulsed electron beam being proportional the pulse wave of high voltage power. This cavity is used to bunch them psec bunch train by velocity modulation. The main specifications of this cavity by low level RF test are following; frequency 238MHz (It is possible to fine-tuning by the tuners), Q-value 15500, coupler coupling β 1.5.
The Japan Atomic Energy Research Institute (JAERI) is promoting the Japan Proton Accelerator Research Project in cooperation with the High Energy Accelerator Research Organization (KEK). The Japan Proton Accelerator is composed of three main parts: a 400 MeV linac, 3 GeV synchrotron ring, and 50 GeV synchrotron ring. This announcement describes the results of a basic design study on the beam transport system (L3BT) connecting the 400 MeV linac and 3 GeV synchrotron ring. The study results are being used to determine the specifications of the respective components of the L3BT.
We have newly developed a compact C-band (5,712MHz) standing-wave accelerator for the medical product/waste sterilization applications. The accelerator consists of an electron gun operating at 25kV DC followed by a single-cell pre-buncher and 3-cell buncher section, and 1 1-cell of the side-coupled standing-wave accelerating structure. The total length including the electron gun is about 600 mm. The first high-power test was performed in March 2000, where the accelerator successively generated the electron beam of 9 MeV energy and 160 mA peak-current at 3.8 MW RF input power. Mitsubishi Heavy Industry starts to serve the sterilization systems using C-band accelerator reported here, and also supplies the accelerator components for the medical oncology applications.
We developed the technology for appling periodic copper electroforming to DTL (drift tube linac) of the Japan Hadron Facility. Highly pure copper is deposited on components of DTL by the copper electroforming. Key techniques which improve productivity or quality of electroformed copper are introduced.
We developed a pure copper lining process for RF cavities using a new copper electroforming, a periodic reverse copper electroforming (PR process ) with a low Cu-content acid copper sulfate bath which contains no organic additives. The PR process offers pure copper that contains impurities less than 35 ppm or so, and that has equivalent IACS (International Annealed Copper Standard) value to that of oxygen-free copper. The lining process can be applied to complex accelerator components such as hollow coils for quadruple magnet. We produced the trial model of DTL (drift tube linac) by using this new electroformed copper lining process and achieved high vacuum and excellent Q value.
The Disk-and-Washer (DAW) linac for electron accelerator is under development by Mitsubishi Heavy Industries, ltd.(MHI) and Kyoto university. In first step, The DAW linac of aluminum model is manufactured and measured RF character to determine the dimension of linac. Next step, OFC model is manufactured to verify the process of brazing assemble. Unfortunately many leak troubles happen at brazig parts. In this paper, the cause of leak and the way of settlement is described.
A HOM (Higher Order Mode) coupler for a 600MHz superconducting linac of the JAERI/KEK Joint Project is described. Design of the coupler is based on coaxial line technique. The filter characteristics of the HOM coupler are calculated by using the HFSS code. The test results of the model HOM coupler are reported. The RF loss in HOM coupler is estimated using HFSS code.
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