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Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*; Fuwa, Yasuhiro; Terunuma, Nobuhiro*
IEEE Transactions on Applied Superconductivity, 34(5), p.4004005_1 - 4004005_5, 2024/08
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)We are developing a correction magnet for charged particle beams using permanent magnets. By rotating the rod of the permanent magnet that generates the magnetic field, the magnetic field can be changed to bipolarity. To verify the principle of this bi-polarity change, a prototype was built, and its performance was evaluated. The performance evaluation of the prototype machine revealed that the inhomogeneity of the remanent magnetization of the permanent magnet has a significant effect on the multipole component. To suppress this effect, a compensating magnet with additional anisotropic intermediate poles is being considered.
Iwashita, Yoshihisa*; Kuriyama, Yasutoshi*; Fuwa, Yasuhiro
IEEE Transactions on Applied Superconductivity, 34(5), p.4904504_1 - 4904504_4, 2024/08
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)A permanent magnet can be used to generate an axisymmetric uniform magnetic field over a long distance. To satisfy Ampere's law, which states that the line-integral value of the magnetic field is zero, a magnetic field region of opposite polarity appears somewhere along the axis while maintaining uniformity in a certain range along the axis. Using this configuration, a magnetic field generator for a Faraday rotation device for laser light was fabricated. This device has a large bore of 30 mm in diameter to handle ultra-high-power lasers and can hold a large crystal disc for Faraday rotation. The irregularity in the central plane is less than 1% within the bore diameter. This configuration can also be applied to long axisymmetric beam transport magnets. This technique can be extended to control the gradient of the magnetic field distributions, such as the focusing field of a klystron.
Fuwa, Yasuhiro; Kitamura, Ryo
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.531 - 534, 2023/11
In the J-PARC LINAC, the beam current and pulse width are being upgraded in order to increase the beam output power for the next decade. MEBT1 (Medium Energy Beam Transport 1) is located between the RFQ and the DTL to form an intermediate bunch structure for matching the transverse and longitudinal beams and for injection into the rapid cycling synchrotron in the later stage. Since the beam energy in MEBT1 section is low (3 MeV), the space-charge effect is expected to increase as the beam intensity increases. In this study, a new magnet has been designed and fabricated to suppress the beam loss caused by the space-charge effect. The new magnet is a combined-function magnet that can generate superimposed multipole components for beam focusing and space-charge effect compensation in a small space, and a permanent magnet is used to reduce the power consumption and the size of the equipment. In this presentation, the design of the magnet and its effect on beam dynamics will be discussed.
Fuwa, Yasuhiro; Moriya, Katsuhiro; Takayanagi, Tomohiro
Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.364 - 367, 2022/09
MEBT1 (Medium Energy Beam Transport 1) of the J-PARC LINAC is a 3 MeV beam transport system located between the RFQ (Radio Frequency Quadrupole) and DTL (Drift Tube Linac). In the MEBT1, the beam-optical matching for injection into DLT and chopping for injection into acceleration phase of 3 GeV synchrotron, located downstream to the LINAC, are performed. The characteristics of MEBT1 are an important factor in determining the beam quality in the J-PARC accelerator facility. To achieve beam power of 1 MW and beyond, improving the stability and reliability of MEBT1 is an important development issue. The application of permanent magnets to the beam focusing system to the MEBT1 is under consideration to achieve improved stability and reliability. In this presentation, we report the design of focusing magnets using permanent magnet material and the results of the lattice study of MEBT1 with permanent magnets.
Fuwa, Yasuhiro; Iwashita, Yoshihisa*; Kondo, Akihiro*
IEEE Transactions on Applied Superconductivity, 32(6), p.4007304_1 - 4007304_4, 2022/06
Times Cited Count：0 Percentile：0.00(Engineering, Electrical & Electronic)High-field magnets are often demanded advanced scientific studies. Although a hybrid coil design comprising Nb-Ti, Nb
Sn, and HTS (High-Temperature Superconductors) are potential candidates for such application, the costs of NbSn and HTS are expensive compared with Nb-Ti. By generating an additional field of about 1 T by permanent magnets, the required amounts of superconducting material may be reduced. Magnetic properties of some magnetic materials have been studied by other works at temperatures as low as 100 K. The remanent field of conventional NdFeB magnets decreases at 100 K due to spin reorientation. PrFeB magnets consisting of praseodymium (Pr) instead of neodymium (Nd) do not show such degradation and the coercivity of PrFeB at 100 K is 7 T. In this study, the B-H curve, as a primary magnetic property, of a PrFeB magnet sample was measured in the temperature range down to 4 K. As a result, no decrease in magnetization of the praseodymium magnets, and the coercivity was 10 T.
Yako, Tomoki*; Iwashita, Yoshihisa*; Abe, Masashi*; Kurihara, Toshikazu*; Fukuda, Masafumi*; Sato, Masaharu*; Sugimura, Takashi*; Fuwa, Yasuhiro; Takamiya, Koichi*; Iinuma, Yuto*
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1003 - 1005, 2019/10
Permanent magnets are used as materials for beam optics elements, but it is known that radiation demagnetization occurs in neodymium magnets and samarium cobalt magnets. However, there is not enough information on the radiation demagnetization of ferrite magnets which is weak in strength but inexpensive. In order to verify the suitability of the ferrite magnet as a beam optics element, radiation demagnetization experiments by neutron irradiation of the ferrite magnet were carried out at the Kyoto University Research Reactor (KUR). In the experiment, neutron fluence up to 
cm
was irradiated, and no significant demagnetization was detected on the fluence.
Abe, Masashi*; Iwashita, Yoshihisa*; Terunuma, Nobuhiro*; Fuwa, Yasuhiro; Yako, Tomoki*
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.700 - 702, 2019/10
Application of permanent magnets to the damping ring of International Linear Collider (ILC) is investigated. Replacing electromagnets with permanent magnets can reduce not only electricity for exciting the coils and maintenance cost of power supplies but also leakage accidents of cooling water. Bending magnets and correction magnets are used in damping ring, but we tried to calculate magnetic field distributions in a correction magnets using permanent magnets with 3D magnetic field code CST studio. The orbit correction magnet requires that the polarity and the intensity of the generated magnetic field be variable in order to correct the beam orbit error. In this research, adjustment of the generated magnetic field was made possible by mounting the rotation mechanism on the permanent magnet in the magnetic circuit in the correction magnet. In addition, in order to suppress deterioration of beam quality due to an incorrect multipole magnetic field, optimization of the shape of the magnetic circuit was performed, and a magnet design that could be installed on a accelerator was established.
Yoshida, Kenichi; Nara, Takayuki; Saito, Yuichi; Yokota, Wataru
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.392 - 393, 2004/08
no abstracts in English
Matsuda, Makoto; Fujii, Yoshio*; Takeuchi, Suehiro; Yoshida, Tadashi
Dai-15-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.62 - 64, 2003/03
no abstracts in English
; Aoto, Kazumi; ;
JNC TN9400 2000-022, 46 Pages, 2000/03
ln this report, a study on the behaviors of the magnetization induced by mechanical damages is carried out. By introducing mechanical damages to a test-piece with a tension or/and a zero, tension fatigue testing and measuring the corresponding leakage flux signal, natural magnetization change is proved and found increasing with the mechanical damages (viz. plastic deformation or fatigue damages) though a saturation occurs when damage gets too large. From the experimental results of fatigue testing utilizing test-pieces with a central slit, it was verified that observing the natural leakage flux density (leakage flux without applying external magnetic field) is a reasonable way to identify fatigue cracks. A feature parameter (area of the 
B hysteresis curve) of the in-situ magnetic field signal measured during the fatigue testing is proposed for predicting the fatigue damages, which is found depending on the cyclic number of the applied loading. At last, residual magnetic fields of a magnetized test-piece are also measured and found depending on the applied plastic deformation in case that the plastic strain is not too small. From these experimental results, it is found that the approach detecting natural magnetization is applicable for monitoring the damage status though it may be not efficient for a scanning inspection concerning its small signal magnitude. On the other hand, the method employing permanent magnet is robust against the environment noise but possibly not valid for the ISl of a structural component with a relative low damage level. For practical application, efforts to evaluate the feasibility of the proposed method are necessary for more testing conditions especially its suitability in a practical environment.
Saito, Yuichi; Yokota, Wataru; Okoshi, Kiyonori
KEK Proceedings 99-22, p.1 - 16, 2000/01
no abstracts in English
Ito, Takao; Yamazaki, Haruyuki*; Usui, Katsutomi; Mogaki, Kazuhiko; Kuriyama, Masaaki
JAERI-Tech 99-066, p.13 - 0, 1999/09
no abstracts in English
Fe
N; ; ; ; ; ; Morii, Yukio; P.C.Canfield*
Physica B; Condensed Matter, 237-238, p.534 - 540, 1997/00
Times Cited Count：6 Percentile：42.00(Physics, Condensed Matter)no abstracts in English
Saito, Yuichi; Yokota, Wataru
Review of Scientific Instruments, 67(3), p.1174 - 1176, 1996/03
Times Cited Count：5 Percentile：47.50(Instruments & Instrumentation)no abstracts in English
Saito, Yuichi
INS-T-534, 0, p.130 - 134, 1995/02
no abstracts in English
Saito, Yuichi; Yokota, Wataru
BEAMS 1995: Dai-6-Kai Ryushisen No Sentanteki Oyo Gijutsu Ni Kansuru Shimpojiumu Koen Rombunshu, 0, p.15 - 18, 1995/00
no abstracts in English
Mo, YFe
Mo and NdFe
CoTiMorii, Yukio; H.Sun*; ; ; ; Funahashi, Satoru
Physica B; Condensed Matter, 213-214, p.291 - 293, 1995/00
Times Cited Count：3 Percentile：25.08(Physics, Condensed Matter)no abstracts in English
Kakuno, Kazunori*; Sasaki, Shigemi; Shimada, Taihei;
JAERI-M 93-156, 27 Pages, 1993/08
no abstracts in English
Kakuno, Kazunori*; Sasaki, Shigemi
JAERI-M 92-157, 11 Pages, 1992/10
no abstracts in English
Sakamoto, Keishi; Maebara, Sunao; ; Kishimoto, Yasuaki; ; Kawasaki, S.*; Nagashima, Takashi; Maeda, Hikosuke;
JAERI-M 91-036, 11 Pages, 1991/03
no abstracts in English
