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Okumura, Susumu; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Yokota, Wataru; Ishimoto, Takayuki*; Kurashima, Satoshi; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
Review of Scientific Instruments, 76(3), p.033301_1 - 033301_6, 2005/03
Times Cited Count：9 Percentile：43.09(Instruments & Instrumentation)A magnetic field drift, gradual decrease of the order of 10
in several tens of hours, was observed with the beam intensity decrease in an operation of an azimuthally-varying-field (AVF) cyclotron. From our experimental results, we show that the temperature increase of the magnet iron by the heat transfer from the excitation coils can induce such change of the magnetic field as to deteriorate the beam quality. The temperature control of the magnet iron was realized by thermal isolation between the main coil and the yoke and by precise control of the cooling water temperature of the trim coils attached to the pole surfaces in order to prevent temperature change of the magnet iron. The magnetic field stability of 
5
10
and the beam intensity stability of 2% have been achieved by this temperature control.
Okumura, Susumu; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Yokota, Wataru; Ishimoto, Takayuki*; Kurashima, Satoshi; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
AIP Conference Proceedings 600, p.330 - 332, 2001/00
Frequent corrections of the magnetic field of the JAERI AVF cyclotron were required for keeping a beam current constant during long time operation. We observed correlation between the magnetic field and the temperature of the cyclotron magnet yoke by measuring the magnetic field with an NMR probe and the temperature with platinum resistance thermometers. The unstable phenomenon of a cyclotron beam was induced by temperature change in the magnet yoke caused mainly by thermal conduction from the main coil. To restrain the thermal conduction to the yoke, we have inserted temperature controlled copper plates between the yoke and the main coil. In addition, a temperature control system of the cooling water of the trim coils has been installed independent of the total cooling system for controlling the pole tip temperature. An optimum condition of the temperature control systems for stabilizing the magnetic field has been investigated.
Okumura, Susumu; Kurashima, Satoshi; Ishimoto, Takayuki*; Yokota, Wataru; Arakawa, Kazuo; Fukuda, Mitsuhiro; Nakamura, Yoshiteru; Ishibori, Ikuo; Nara, Takayuki; Agematsu, Takashi; et al.
Proceedings of 13th Symposium on Accelerator Science and Technology, p.283 - 285, 2001/00
no abstracts in English
Nakamura, Yoshiteru; Ishibori, Ikuo; Okumura, Susumu; Nara, Takayuki; Yokota, Wataru; Fukuda, Mitsuhiro; Agematsu, Takashi; Arakawa, Kazuo; Mizuhashi, Kiyoshi; Sano, M.*; et al.
JAERI-M 94-007, 74 Pages, 1994/02
no abstracts in English
Nakamura, Yoshiteru; Arakawa, Kazuo; Mizuhashi, Kiyoshi; Yokota, Wataru; Kamiya, Tomihiro; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Okumura, Susumu; Ishibori, Ikuo; et al.
Proc. of the 8th Symp. on Accelerator Science and Technology, p.194 - 196, 1991/00
no abstracts in English
Seki, Masami; Honda, Masao; ; Sakamoto, Keishi; Imai, Tsuyoshi; *; *
Terebijon Gakkai Gijutsu Hokoku, 12(15), p.1 - 6, 1988/00
no abstracts in English
