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Harada, Hiroyuki; Hayashi, Naoki
JPS Conference Proceedings (Internet), 33, p.011027_1 - 011027_6, 2021/03
The transverse betatron tune is one of the most important key parameters in a ring accelerator because emittance growth and beam loss occur directly in case of crossing a betatron resonance. Especially, the tune must be required a controll with high accuracy in high intensity proton accelerator from the view point of space charge force and the beam instability. In general measurement method, the betatron tune is measured by analyzing the detected beam oscillation on Fourier transform. However, the beam is quickly accelerated and the revolution frequency of the beam changes quickly in a rapid cycling synchrotron. So, the tune accuracy is not improved. A new method was developed for high resolution analysis of the tune and was evaluated in J-PARC accelerator. Tune accuracy was successfully improved from 0.013 to less than 0.001. Tune controll with high accuracy is base for high-intensity beam. In this paper, the new method is introduced and the measured result in J-PARC is report.
Sawamura, Sadashi*
JNC TJ8400 2000-053, 41 Pages, 2000/02
Dose evaluation for direct radiation and skyshine from nuclear fuel facilities is one of the environment evaluation items. This evaluation is carried out by using some shielding calculation codes. Because of extremely few benchmark data of skyshine, the calculation has to be performed very conservatively. Therefore, the benchmark data of skyshine and the well-investigated code for skyshine would be necessary to carry out the rational evaluation of nuclear facilities. The purpose of this study is to obtain the benchmark data of skyshine and to investigate the calculation code for skyshine. In this fiscal year, the followings are investigated; (1)To improve the detection sensitivity of pulsed neutron measurement, two neutron detectors and some electronic circuits are added to the system constructed last year. (2)To estimate the neutron dose at the distant point from the facility instead of the commercialized rem-counter, a 
He detector with paraffin moderator is equipped to the system. (3)Using the new detection system, the skyshine of neutrons from 45Mev LINAC facility was measured in the distance up to 300m. The results show that the time structure of pulsed neutrons almost disappears at the further points than 150m. (4)In the distance from 90m to 300m ordinal total counting method without gate pulse are applied to detect the neutrons. (5)The experimental results of space dependency up to 300m is fitted fairly well by the Gui's response function.
Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo; Ishibori, Ikuo; Matsumura, Akihiko*; *
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.300 - 301, 1997/00
no abstracts in English
Fukuda, Mitsuhiro; S.Adam*
JAERI-Conf 95-021, 0, p.344 - 346, 1995/10
no abstracts in English
Harada, Hiroyuki; Hayashi, Naoki
no journal, ,
Transverse beam oscillation frequency (betatron tune) is measured by detecting the beam position with detect time of T and analyzing Fourier transform. The tune accuracy depends on frequency resolution of 1/T. In a rapid cycling synchrotron, a beam is quickly accelerated and then revolution frequency is quickly changed. So, detect time of T is limited for tune measurement and then tune accuracy is not improved. We apply a new analyzing method. As the result, tune accuracy is improved from 0.013 to less than 0.001. So, we can control well tune tracking during acceleration and this result is base for high-intensity beam power. In this presentation, we will report the new method and results.
