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| TUPB109 | Assembly and Cool-Down Tests of STF2 Cryomodule at KEK | 888 |
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| As the next step of the quantum beam project, the STF2 project is in progress at KEK. Eight 9-cell SC cavities and one superconducting quardrapole magnet were assembled into the cryomodule called CM1. Four 9-cell SC cavities were assembled into the cryomodule called CM2a. These two cryomodules were connected as one unit, and the examination of completion by a prefectural government was carried out. The target value of beam energy in the STF2 accelerator is 400 MeV with a beam current of 6 mA. The first cool down test for low power level RF measurements was performed in autumn of 2014. In this paper, the assembly procedure of the STF2 cryomodules and the results of the low-power measurement are reported. | ||
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| WEBA06 | Design Studies for Quarter-Wave Resonators and Cryomodules for the Riken SC-LINAC | 976 |
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| Recently we proposed a new project aimed at intensity upgrade of uranium beams of RIKEN RIBF. In this new project, construction of a superconducting linac is planned replacing the injector cyclotron so called RRC. The RIKEN superconducting linac consists of 14 cryomodules each of which contains four quarter-wave-resonators (QWRs) in each. The QWR operates at an rf frequency of 73 MHz in the continuous wave mode with beta as low as 0.055-1.008. A coaxial probe-type RF fundamental power-coupler which transmits RF power of several kW will be utilized for beam loading of 1.3 kW/resonator at the maximum with Qext of several x106. Tuning of the resonant frequency will be realized with a mechanical tuner pressing the resonator wall in the direction parallel to the beam. This year, we started a development of a test cryomodule with SC-QWRs. In this paper, design studies for a SC-QWR and its cryomodule, e.g., QWR, coupler, and, tuner will be presented together with a construction schedule of the prototype. Prototyping of a superconducting cavity and its test cryomodule was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). | ||
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Slides WEBA06 [17.564 MB] | |
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| THPB030 | Fabrication and Evaluation of Low RRR Large Grain 1-Cell Cavity | 1146 |
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Successive R&D studies of SRF cavities are ongoing at KEK by using existing facilities of Cavity Fabrication Facility (CFF) and other equipment of Superconducting Test facility (STF). Recently, there are studies on the low RRR of niobium material with high and uniform concentration of tantalum which could be used for the fabrication of high performance SRF cavity, and hence it could reduce the fabrication cost of cavities [1]. In order to confirm the advantage of the material, a large-grain single-cell cavity was fabricated at CFF/KEK with sheets sliced from a low RRR niobium ingot with high and uniform concentration of tantalum. The resistivity measurement of sample from sliced sheet showed the RRR value of 100, whereas it is about 400 for the nominal qualification of fine-grain sheets at KEK. The low RRR large-grain single-cell cavity was already fabricated at CFF/KEK. The quality control of the fabrication processes are well under control. Then several vertical tests of the cavity were done at STF/KEK. In this presentation, the results of the vertical tests are shown. The potential of the low RRR niobium material for SRF cavity are discussed.
*P.Kneisel et al, NIM A774(2015)133 |
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| THPB059 | Design, Fabrication and Performance of SRF-Gun Cavity | 1243 |
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| The development of superconducting RF gun has been started at KEK. The performance targets are that average current is 100 mA, normalized emittance is less than 1 μm.rad, beam energy is 2 MeV and energy spread is less than 0.1 %. The SRF gun consists of 1.3 GHz and 1.5 cell elliptical cavity and backward illuminated photocathode. The cavity shape was designed by using SUPERFISH and GPT. The cavity has been fabricated by Japanese industry. Accelerating field tuning and vertical test without cathode plug was done. The surface peak electric field reached 66 MV/m, and this meet the target value 42 MV/m sufficiently. For next vertical test, cathode rod without photocathode is in preparation. In the workshop, the SRF-Gun concepts and vertical test results will be reported. | ||
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| THPB082 | Design of QWR Power Coupler for the Rare Isotope Science Project in Korea | 1326 |
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| A power coupler has been designed for the Rare Isotope Science Project (RISP) in Korea. The power couplers will provide 4 kW RF power to 81.25 MHz superconducting quarter wave resonators with β=0.047. The coupler is a coaxial capacitive type with an impedance of 50 ohms using a disc type ceramic window. Design studies of the coupler are presented. | ||
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| THPB084 | Design of Input Coupler for RIKEN Superconducting Quarter-Wavelength Resonator | 1335 |
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| In RIKEN Nishina Center, for the purpose of development of elemental technology for the superconducting linear accelerator, the designing and construction of accelerator system based on superconducting quarter-wavelength resonator are carried out. The basic designs of the input coupler are as follows: The resonance frequency of the cavity is 75.5 MHz and assumed beam loading is about 1 kW. Double vacuum windows, which are disk-type, are adopted. A thermal anchor of 40 K is installed near the cold-window. The optimum positions of the cold-window and the thermal anchor depending on the effective RRR of copper-plate are being studied. In this contribution, the details of these designs will be reported. This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). | ||
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