IPAC2012 - List of Authors (Nakamoto, T.)

Paper

Title

Page

High Field Magnet Developments

3185

T. Nakamoto
KEK, Ibaraki, Japan

Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.

Slides THYA01 [7.578 MB]

THPPD024

Irradiation Effects in Superconducting Magnet Materials at Low Temperature

3551

M.Y. Yoshida, M.I. Iio, S. Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, M. Sugano, K. Yoshimura
KEK, Ibaraki, Japan
M. Aoki, T. Itahashi, Y. Kuno, A. Sato
Osaka University, Osaka, Japan
Y. Kuriyama, Y. Mori, B. Qin, K. Sato, Q. Xu, T. Yoshiie
Kyoto University, Research Reactor Institute, Osaka, Japan

Superconducting magnets for high intensity accelerators and particle sources are exposed to severe radiation from beam collisions and other beam losses. Neutron fluence on the superconducting magnets for the next generation projects of high energy particle physics, such as LHC upgrades and the COMET experiment at J-PARC, is expected to exceed 10²¹ n/m², which is close to the requirements on the fusion reactor magnets. Irradiation effects at low temperature in superconducting magnet materials should be reviewed to estimate the stability of the superconducting magnet system in operation and its life. The pion capture superconducting solenoids for the COMET experiment are designed with aluminum stabilized superconducting cable to reduce the nuclear heating by neutrons. Also, the heat is designed to be transferred in pure aluminum strips. Irradiation effects on the electrical conductance of aluminum stabilizer and other materials are tested at cryogenic temperature using the reactor neutrons. This paper describes the study on the irradiation effects for the magnet developments.

Paper	Title	Page
THYA01	High Field Magnet Developments	3185
	T. Nakamoto KEK, Ibaraki, Japan
	Superconducting magnets for future accelerators need to generate a field beyond 10 T. However, mature NbTi superconductors which have been already operated at its performance limit at LHC cannot be adopted. Instead, A15 type superconductors have been considered to be promising materials for the high field magnets. Especially, intensive R&D efforts for the LHC luminosity upgrade with state-of-the-art Nb3Sn superconductors have been carried out. Further future accelerators such as the High-Energy LHC and muon accelerators must require the high field reaching 20 T or more. This means that utilization of HTS (high Tc superconductors) would be the only possible solution. However, it is known that these advanced superconductors are not mechanically robust in comparison with the practical NbTi and the performance is influenced by mechanical stress and strain. In addition, magnetization effects caused by larger effective filament diameters may compromise the field quality in the accelerators. The magnet developments to overcome these issues are ongoing. This presentation will try to review the US and worldwide high field accelerator magnet developments: achievements, status, and plans.
	Slides THYA01 [7.578 MB]

THPPD024	Irradiation Effects in Superconducting Magnet Materials at Low Temperature	3551
	M.Y. Yoshida, M.I. Iio, S. Mihara, T. Nakamoto, H. Nishiguchi, T. Ogitsu, M. Sugano, K. Yoshimura KEK, Ibaraki, Japan M. Aoki, T. Itahashi, Y. Kuno, A. Sato Osaka University, Osaka, Japan Y. Kuriyama, Y. Mori, B. Qin, K. Sato, Q. Xu, T. Yoshiie Kyoto University, Research Reactor Institute, Osaka, Japan
	Superconducting magnets for high intensity accelerators and particle sources are exposed to severe radiation from beam collisions and other beam losses. Neutron fluence on the superconducting magnets for the next generation projects of high energy particle physics, such as LHC upgrades and the COMET experiment at J-PARC, is expected to exceed 10²¹ n/m², which is close to the requirements on the fusion reactor magnets. Irradiation effects at low temperature in superconducting magnet materials should be reviewed to estimate the stability of the superconducting magnet system in operation and its life. The pion capture superconducting solenoids for the COMET experiment are designed with aluminum stabilized superconducting cable to reduce the nuclear heating by neutrons. Also, the heat is designed to be transferred in pure aluminum strips. Irradiation effects on the electrical conductance of aluminum stabilizer and other materials are tested at cryogenic temperature using the reactor neutrons. This paper describes the study on the irradiation effects for the magnet developments.