Background issues encountered by cold-neutron chopper spectrometer AMATERAS

Kikuchi, Tatsuya*; Nakajima, Kenji; Kawamura, Seiko; Inamura, Yasuhiro; Nakamura, Mitsutaka; Wakai, Daisuke*; Aoyama, Kazuhiro*; Iwahashi, Takaaki*; Kambara, Wataru*

Physica B; Condensed Matter, 564, p.45 - 53, 2019/07

https://doi.org/10.1016/j.physb.2019.02.015

Details of the background, that is, unwanted signals accumulated by the data acquisition system of neutron instruments, observed by the cold-neutron chopper spectrometer AMATERAS installed at the Materials and Life Science Experimental Facility at J-PARC are reported. In the design phase of AMATERAS, we carefully considered the achievement of high signal-to-noise ratio, and possible countermeasures were implemented. Actually, recent scientific outputs from AMATERAS indicates that the spectrometer is one of excellent neutron instruments with low background. In spite of that, in nine years of AMATERAS operation, we have encountered unwanted signals due to various reasons, including gamma-rays emitted at materials on or near the beam line including the sample itself, scattered neutrons from the beam line devices, air scattering, electronic noise in data acquisition system, cosmic rays, T0 burst, and other unknown sources. In this report, we discuss the background observed by AMATERAS, especially in the conditions of without samples, comprehensively. The possible sources of these signals and the countermeasures considered against the above sources are discussed, which may be helpful to those who are engaged in other existing or planned neutron-scattering instruments.

Study on use of superconducting magnet and first inelastic neutron scattering experiment under magnetic field at 4SEASONS spectrometer

Kajimoto, Ryoichi; Ishikado, Motoyuki*; Kira, Hiroshi*; Kaneko, Koji; Nakamura, Mitsutaka; Kamazawa, Kazuya*; Inamura, Yasuhiro; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Murai, Naoki; et al.

Physica B; Condensed Matter, 556, p.26 - 30, 2019/03

BB2018-0570.pdf:2.17MB

https://doi.org/10.1016/j.physb.2018.11.065

Recent issues encountered by AMATERAS; A Cold-neutron disk-chopper spectrometer

Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya*; Kofu, Maiko; Kawakita, Yukinobu; Inamura, Yasuhiro; Kambara, Wataru*; Aoyama, Kazuhiro*; Wakai, Daisuke*; Harada, Masahide; et al.

Journal of Physics; Conference Series, 1021(1), p.012031_1 - 012031_5, 2018/06

https://doi.org/10.1088/1742-6596/1021/1/012031

Oscillating radial collimators for the chopper spectrometers at MLF in J-PARC

Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Aoyama, Kazuhiro; Kajimoto, Ryoichi; Nakajima, Kenji; Kawamura, Seiko; Ikeuchi, Kazuhiko*; Kikuchi, Tatsuya; Inamura, Yasuhiro; et al.

JPS Conference Proceedings (Internet), 8, p.036011_1 - 036011_6, 2015/09

The needs for inelastic neutron scattering experiments under the special sample environment such as strong magnetic field and high temperature are recently increasing. However, the unwanted scatterings originating from these devices affect the detection of weak inelastic signals. In order to overcome this problem we have developed an oscillating radial collimator specialized for the chopper spectrometer at Materials and Life Science Experimental Facility (MLF) in J-PARC. In this study, we will report the performances of newly-developed oscillating radial collimators both for 4SEASONS and AMATERAS.

Fuel Failure Simulation Test in JOYO; FFDL in-pile test(III)

Ito, Chikara; Ito, Hideaki; Ishida, Koichi; Hatoori, Kazuhiro; Oyama, Kazuhiro; Sukegawa, Kazuya*; Murakami, Takanori; Kaito, Yasuaki; Nishino, Kazunari; Aoyama, Takafumi; et al.

JNC TN9410 2005-003, 165 Pages, 2005/03

JNC-TN9410-2005-003.pdf:12.66MB

At experimental fast reactor JOYO, appraisal of detection efficiency of behavior and FFD and FFDL of the fission product which is discharged inside the furnace as one of safety research of the country, is carried out. In MK-II core, the slit in the gas plenum part of the test sub-assembly, the test which irradiates this(1985 April, FFDL in-pile test(I)), providing the slit in the fuel column part of the test sub-assembly, the test which it irradiates(1992 November, FFDL in-pile test(II)) were carried out.MK-III reactor core replacement was completed and started in 2004. That the behavior in the system of FP with the reactor core replacement and so on changes in the MK-III reactor core and to have an influence on the sensitivity and the replying of FFD and FFDL are thought of. Therefore, behavior of FP in the fuel failure in the MK-III reactor core, the performance of FFD and FFDL must be confirmed beforehand. Moreover, to prepare for the fuel failure and the RTCB test which is doing a future plan, and to confirm a plant operation procedure in the fuel failure in MK-III reactor core operation and to attempt for the correspondency to improve are important.Therefore, in the period from 2004 November 11th to November 29th, it carried out the FFDL in-pile(III). It did a series of plant operation to stop a nuclear reactor after loading a reactor core center with the fuel element for the test which provided an artificial slit for the fuel cladding in the MK-III reactor core and irradiating it and detecting fuel damaging and to take out fuel. And it confirmed the operation procedure of the fast reactor in the fuel failure.Also, the improvement items such as the improvement of the operation and the procedure and the remodeling and the service of the facilities could be picked up. In the future, it attempts these compatible, and it prepares for the MK-III reactor core operation and it incorporates a final examination result by the improvement of the safety of FBR.

JOYO-CEFR Technical Information Exchange Meeting

Oyama, Kazuhiro; Aoyama, Takafumi

JNC TN9200 2003-005, 175 Pages, 2004/03

JNC-TN9200-2003-005.pdf:17.64MB

On 2004 February 26th it hosted the conference which does a communication about the current status and the technical development,etc of JOYO , CEFR and MONJU.Through the meeting, a discussion was done for the information exchange meeting and the mutual sending of the technical expert as the cooperation of the future. We were possible to confirm about the field to be interested in CEFR.

Performance evaluation test of radial collimators for chopper spectrometer at J-PARC

Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Aoyama, Kazuhiro; Yamauchi, Yasuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.

no journal, , 

In recent years, the need for neutron inelastic scattering experiments in special environments under the strong magnetic field and the high temperature is increasing. On the other hand, there is a problem that the unnecessary scattering originating from the sample environment devices affects the detection of weak inelastic signals. To solve this problem, we have been developing the radial collimator for chopper spectrometer at J-PARC. In this talk, we plan to introduce the performance evaluation results of our radial collimator.

Development of radial collimators for chopper spectrometer at J-PARC

Nakamura, Mitsutaka; Kawakita, Yukinobu; Kambara, Wataru; Yamauchi, Yasuhiro; Aoyama, Kazuhiro; Kajimoto, Ryoichi; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Inamura, Yasuhiro; Nakajima, Kenji; et al.

no journal, , 

Recently, there is a growing need for neutron inelastic scattering experiments under special sample environments such as strong magnetic field and high temperatures. However the unwanted scattering originating from the sample environment equipment adversely affect the detection of weak inelastic signal. In order to overcome these difficulties, we have developed the radial collimators for chopper spectrometers at J-PARC. In this report we will show the results of performance evaluation tests for radial collimators.

5 years of a cold-neutron disk-chopper spectrometer, AMATERAS

Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kawakita, Yukinobu; Inamura, Yasuhiro; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Tanaka, Hiromichi; Iwahashi, Takaaki; Kambara, Wataru; et al.

no journal, , 

AMATERAS is a cold-neutron multi disk-chopper spectrometer at J-PARC. AMATERAS is designed to realize high intensity and fine and flexible energy resolution measurements in quasielastic and inelastic neutron scattering experiments from cold to thermal neutron energy region. AMATERAS had the first neutron beam in May 2009. After then, experiments of more than 70 proposals (including 17 in house projects proposals) have been carried out and results were distributed as 15 scientific papers and more than 100 presentations at domestic and international scientific meetings by users.

Development of various shielding devices to suppress background in J-PARC

Kambara, Wataru; Aoyama, Kazuhiro; Yamauchi, Yasuhiro; Iwahashi, Takaaki; Ono, Shino; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Shibata, Kaoru; Nakajima, Kenji; Kawamura, Seiko; et al.

no journal, ,