Kaneko, Koji; Kakihana, Masashi*; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Hamon, 30(3), p.160 - 165, 2020/08
no abstracts in English
Hamon, 30(2), p.90 - 93, 2020/05
no abstracts in English
Hamon, 30(1), p.45 - 50, 2020/02
no abstracts in English
Sugiyama, Masaaki*; Inoue, Rintaro*; Nakagawa, Hiroshi; Saio, Tomohide*
Hamon, 30(1), p.16 - 25, 2020/02
Neutron has distinct features as a scattering probe to analyze structure and dynamics of biological macromolecules. The theme of this review is to try to describe how we did/do utilize them. And "How we should utilize them more effectively in the trend of integrative structural biology?" with solution scattering.
Hamon, 30(1), p.7 - 8, 2020/02
Safety review of JRR-3 under the New Regulatory Requirements was completed on 7th November 2018. Neutron beam will come back in early 2021 after reinforcement works of the roof of the reactor building, the peripheral structures like a stack, a cooling tower, and the experimental hall. The future of neutron sciences using the research reactor strongly depends on how many impacted researches using JRR-3 are achieved after restarting JRR-3. At this stage, we can learn a lot of things from the back numbers of HAMON.
Kawakita, Yukinobu; Kikuchi, Tatsuya*
Hamon, 29(2), p.91 - 94, 2019/05
Bismuth (Bi) has a double-layered structure based on Peierls distortion in crystalline phase. Complicated static structure in liquid phase which cannot be interpreted by a simple packing model has been conjectured that Peierls distortion may remain even in liquid phase. We measured quasi-elastic neutron scattering (QENS) of liquid Bi by using AMATERAS installed at BL14 beamport of Materials and Life Science Experimental Facility (MLF) in J-PARC and analyzed coherent QENS spectra. A time-space correlation function revealed that the nearest neighboring shell followed by a shoulder-like structure at longer side consists of four contributions of short and long correlations with relatively long relaxation time of a few tens pico second and medium-ranged and the longest correlations with a short relaxation time of sub-pico second, which is a direct observation of the existing layered structure in liquid Bi. In this article, we report the above scientific results and the method to analyze coherent QENS by the time-space correlation function.
Hamon, 28(4), p.204 - 207, 2018/11
A Neutron guide is one of the devices to transport neutron beam for long distance without sacrificing much neutrons; therefore, it can supply neutrons to many experimental instruments distributed in a large experimental hall. Also, by using a curved guide, only the neutrons in a required energy range can be transported, and rays and fast neutrons can be effectively eliminated, therefore the signal to background ratio is improved. In addition, a neutron beam can be branched by applying curved guides. Neutron guides are also used to control the divergence angle and intensity of the neutron beam supplied to the neutron instrument.
Hamon, 28(4), p.208 - 211, 2018/11
Adequate shielding of neutrons and associated -rays is of importance from viewpoints of the radiation safety of researchers and good experimental data taking by reducing the background. This article introduces basics of neutron shielding, physics and suitable materials for neutron and -ray shielding, and an example of conceptual shielding design for the 1-MW spallation neutron source of J-PARC MLF.
Hiraka, Haruhiro*; Yamaguchi, Yasuo*; Maruyama, Ryuji; Oku, Takayuki; Ino, Takashi*
Hamon, 28(3), p.144 - 149, 2018/08
no abstracts in English
Hamon, 28(2), p.99 - 102, 2018/05
A thermal neutron reactor operates by the fission of uranium, a nuclear reaction which produces neutrons of energies in the range of MeV. This is far too high an energy to be useful for neutron scattering experiments. Therefore in a research reactor which has neutron beam utilization there are moderators arranged around the primary source to slow down the source neutrons to useful energies. Additionally almost major research reactors include at least one cold neutron source, a special moderator maintained at cryogenic temperature, where neutrons can equilibrate to lower average energies.
Hamon, 28(1), p.26 - 28, 2018/02
We briefly introduce the pedigree of the backscattering neutron spectrometer and the specification of DNA; a time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), with Si crystal analyzers which was constructed at the Materials and Life Science Experimental Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC).
Hamon, 27(4), p.155 - 158, 2017/11
The pulsed spallation neutron source driven by a high-power accelerator is one of the most powerful apparatus to provide high intensity and high quality neutrons with narrow pulse width for conducting cutting-edge researches in several domains of materials and life science. In this system, proton beams of several kW to MW order extracted from the high power accelerator is injected into a target, which is heavy metal, to generate vast amount of neutrons via the spallation reactions with the target nuclei, and slows down these neutrons to thermal to cold neutrons with a moderator and a reflector. Resultant neutron beams are then supplied to a suit of the state-of-the-art experimental devices. In this paper, mechanism to produce neutron beams and outline of the spallation neutron source, engineering design of a target system such as a mercury target, and technical topics to solve the pitting damage problem of the target vessel which is caused by the pressure wave of up to 40MPa at maximum generated in the mercury by the pulsed proton beam injection are reviewed by referring mainly to the mercury target system of the pulsed spallation neutron source at J-PARC.
Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami
Hamon, 27(3), p.104 - 108, 2017/08
Hydrogen is the most abundant element in the solar system and is considered to be one of the promising candidates of the light elements in the Earth's core. However, the amount of hydrogen dissolved in the core and its process are still unknown because hydrogen cannot be detected by X ray and easily escapes from iron at ambient conditions. In this study, we have conducted high-pressure and high-temperature in-situ neutron diffraction experiments on the iron-hydrous mineral system using PLANET in J-PARC. We observed that the water, which was dissociated from a hydrous mineral, reacted with iron to form both iron oxide and iron hydride at about 4 GPa. Iron hydride remained stable after further increase in temperature. This formation occurred at 1000K, where no materials melted. This suggests that hydrogen dissolved into iron before any other light elements dissolved in the very early stage of the Earth's evolution.
Hamon, 27(3), p.109 - 112, 2017/08
A various kinds of radioactive neutron sources have been developed since neutron had been first discovered. The reactions which are mainly taken advantage for generating neutrons as radioactive neutron source are (,n) reaction, (,n) reaction and nuclear fission reaction. Only Am-Be and Cf neutron sources are now available due to reliable reproducibility of neutron emission, long half-lives and less disturbing ray emission. Both are designated as a "reference neutron source" by ISO 8529 series describing principle of establishment of neutron calibration field. Total neutron emission rate from neutron source must be well defined in terms of sophisticated method by national metrological laboratory. Correction factor for anisotropic emission from cylindrical-shaped neutron source must be experimentally determined for neutron fluence rate at a point of test in the calibration laboratory.
Oba, Yojiro*; Morooka, Satoshi; Sato, Hirotaka*; Sato, Nobuhiro*; Inoue, Rintaro*; Sugiyama, Masaaki*
Hamon, 26(4), p.170 - 173, 2016/11
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*
Hamon, 26(2), p.85 - 90, 2016/05
PLANET is the first neutron powder diffractometer dedicated to high-pressure and high-temperature experiments in the World. The six-axis press designed for this beamline enables routine data collection at pressures and temperatures up to 10 GPa and 2000K. In this article, we introduce how the PLANET had been constructed.
Nakatani, Takeshi; Inamura, Yasuhiro
Hamon, 26(1), p.42 - 45, 2016/02
In the Materials and Life science experimental Facility (MLF) of J-PARC, the computing environment group was organized from the construction of MLF. The group has been developed and operated the neutron event-recording data acquisition (DAQ) system, the data analysis library and the device control software framework for neutron experimental instruments in MLF. In this article, we report the new developments as follows: The universal event-recording DAQ system to make the most of the intense neutrons; the data process framework to enable multi-dimensional data analysis at various neutron instruments; the remote access to be easily able to monitor a measurement status and handle many kinds of enormous data from anytime, anywhere.
Hamon, 26(1), p.18 - 20, 2016/02
This is my memory for Prof. Noboru Watanabe in KENS around 1990. My scientific career would not have been possible without the initial encouragement and instruction of Watanabe-sensei who acted as my Ph.D supervisor and introduced me, with enthusiasm, to the subject of pulsed neutron scattering.
Aso, Tomokazu; Yamauchi, Yasuhiro; Kawamura, Seiko
Hamon, 25(4), p.283 - 287, 2015/11
Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito
Hamon, 25(4), p.277 - 282, 2015/11
We introduce the basic principle of neutron radiography technique, and the brief review of its applications. Most of works in this article have been performed at TNRF, Tokai, Japan. Neutron radiography is a nondestructive testing method, so that this technique is used for not only academic studies but also industrial applications. Keywords: neutron radiography, imaging, TNRF