Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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(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.
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.
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.
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：42.7(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：47.82(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：25.66(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
Takeda, Masayasu; Suzuki, Junichi*
no journal, ,
no abstracts in English
Fuwa, Yasuhiro; Iwashita, Yoshihisa*
no journal, ,
In the development of quantum beam applications, increasing the beam intensity is an important issue to achieve efficient beam utilization. One of the most important problem to be solved in realizing intense beam is the suppression of the emittance growth of the beam caused by the space charge effect. In this study, we report the basic design of a magnet that realizes the application of a multipole magnet component to a beam transport line, which was proposed as a means to suppress the new space charge effect. In this magnet, a permanent magnet is used to efficiently generate the multipole component, and by giving the permanent magnet a movable mechanism, the strength of the multipole component can be adjusted and utilized for transporting various beams.
Fuwa, Yasuhiro; Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*
no journal, ,
Radiation demagnetization by neutron irradiation has been measured using the Kyoto University research reactor to evaluate the radiation resistance of permanent magnet materials used for beam optics of accelerators. In the demagnetization evaluation, it is essential to measure the magnetization before and after neutron irradiation accurately, but in the case of measuring the magnetic field using a Hall probe, the displacement of the measured value due to the probe position is relatively large and causes errors in the demagnetization evaluation. In order to realize magnetization measurement with less systematic error, we have developed a method to measure the magnitude of magnetization from the induced electromotive force on coils by rotating the magnet near the coil. By adopting this rotating-magnet method for magnetization measurements, the error of the measured value can be reduced to 0.1%, and the measurement accuracy of radiation demagnetization has been improved.
Fuwa, Yasuhiro; Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*; Hirota, Katsuya*; Yamada, Masako*; Kitaguchi, Masaaki*; Shimizu, Hirohiko*
no journal, ,
A neutron mirror with a magnetic repulsive wall is under development. Since neutrons have a magnetic dipole moment, they are subject to forces in a magnetic field gradient. Using this phenomenon, a potential wall for neutrons can be formed by arranging permanent magnets in a planar configuration of a Halbach array. This potential wall acts as a mirror for a polarized neutron beam. A prototype mirror 20 mm high and 30 mm wide was fabricated, and preliminary neutron reflection experiments were conducted at the MINE2 port of JRR-3. As the next step, we plan to fabricate a mirror with a larger size and conduct experiments at the J-PARC MLF. In this presentation, the principle of the mirror, the results of preliminary experiments at JRR-3, and the status of the mirror fabrication for the experiment at J-PARC will be reported.
