Superconducting Proton Linac Research Articles

ICONE11-36485 R & D Status of Superconducting Proton Linear Accelerator for ADS at JAERI

An accelerator driven nuclear transmutation system (ADS) requires high intensity proton beam; the energy is about 1GeV and the beam power is several tens MW. A superconducting proton linear accelerator is most promising option to provide the high power proton beam. R&D of the superconducting proton linear accelerator began in 1995 at JAERI in collaboration with High Energy Accelerator Research Organization (KEK). As the first step of the R&D, 600MHz superconducting single-cell and 5-cell cavities of beta (ratio of the beam velocity to the light velocity)=0.5,0.6 and 0.9 were fabricated and tested. Surface peak fields (Esp) of the cavity up to 51 and 40 MV/m were obtained at 2K for the single-cell and 5-cell cavities, respectively. The results are good enough for utilization of a high intensity proton accelerator. As the next step of the R&D work, prototype cryomodule has been fabricated in order to demonstrate the cavity performance in the cryomodule. The cryomodule includes two 5-cell cavities of beta=0.6 and is designed to perform 2K operation. Assembly and installation of the cavities in the cryomodule were carried out in the clean room to avoid dust contamination. The design field strength of Esp=16MV/m were obtained in the preliminary test of the cryomodule. The High Intensity Proton Accelerator Project is promoting by JAERI and KEK. A superconducting proton linear accelerator is planned in the energy range from 400 to 600 MeV. The proton beams of 600 MeV will be delivered to the Transmutation Experimental Facility. System design of the superconducting proton linac has been carried out; a cryomodule includes two 972MHz 9-cell cavities and 11 cryomodules are necessary for the acceleration from 400 to 600 MeV at Esp=30 MV/m. Total length of the superconducting linear accelerator is designed to be 58m.

511 超伝導加速空胴の室温時および極低温冷却時における強度(オーガナイズドセッション : 計算力学と構造最適化)

JHF/NSP joint project managed by KEK and JAERI has been proposed with a superconducting proton linac. Because elliptical superconducting cavities for lower velocity have the flattered shape, mechanical properties against the vacuum load and the Lorentz force detuning are very important. In addition to this, thermal stress caused by different expansion coefficients of Niobium and stainless steel needs to be evaluated at the cryogenic temperature. In this paper, mechanical characteristics of superconducting cavities are studied by using structural and electromagnetic analysis.

Development of superconducting cavities for high intensity proton accelerator at JAERI

The Japan Atomic Energy Research Institute (JAERI) is proposing a high intensity proton accelerator for the Neutron Science Project. A superconducting (SC) RF structure is the main option for the high energy part of the linac. Design and development work of the SC proton linac is in progress in JAERI. Three single-cell SC prototype cavities were fabricated and their performances were tested. The test results were good enough to apply to the SC linac. This paper describes the present status of the design and development work for the SC proton linac.

Design and construction of superconducting quadrupole magnets at Karlsruhe

Two types of superconducting quadrupole magnets have been developed: 6 extremely short doublets with a quadrupole length of nearly 11 cm as beam focusing elements in the Karlsruhe superconducting proton linac; 2 quadrupoles of about 1 m length for use in the hyperon experiments at the CERN SPS. The concept for these quadrupoles is a one current block winding per pole, calculated with respect to minimum field errors. Special mechanical and winding techniques have been developed to get the high geometric accuracy required for such air coils. The short doublets must be operated in persistent current mode with a thermal superconducting switch and a required time constant of τ > 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> hours. The hyperon beam quadrupoles must operate reliably for a long time in an inaccessible concrete shielding. The performance of the quadrupoles will be reported.