Deformation texture and dislocation density evolution for multilayer metals with laminate/network interface during in situ tensile deformation

Liu, B. X.*; Lin, Z. M.*; Sato, Shigeo*; Xu, P. G.; Yin, F. X.*

no journal, , 

Cloud application suite for neutron reflectometry

Aoki, Hiroyuki; Kasai, Satoshi*

no journal, , 

New approach to the analysis of the spectral modification of vector meson in nuclei using PHSD transport approach

Ichikawa, Masaya; Gubler, P.; Naruki, Megumi*; Yokkaichi, Satoru*

no journal, , 

Structural analysis of perfluorinated sulfonic acid ionomers (PFSAs) using small angle neutron scattering

Uzuki, Shigeki; Takata, Shinichi

no journal, , 

Concept of spin-echo modulated SANS measurement at MLF

Hiroi, Kosuke; Hayashida, Hirotoshi*; Shinohara, Takenao

no journal, , 

Characterization of fatigue crack-tip stress fields using neutron Bragg edge imaging and diffraction

Su, Y. H.; Shinohara, Takenao; Parker, J. D.*; Oikawa, Kenichi; Kai, Tetsuya; Gong, W.; Harjo, S.; Kiyanagi, Yoshiaki*

no journal, , 

Development of Li-glass fiber detector as a neutron flux monitor

Tsuchikawa, Yusuke; Watanabe, Kenichi*; Oshima, Yuya*; Saito, Yutaro*; Parker, J.*

no journal, , 

In state-of-the-art neutron experiments requiring precise measurements, it is often important to monitor fluctuations of the incident neutron flux. Small fluctuations in measured neutron intensity that cannot be explained by that of proton beam flux are expected to be caused by various factors, such as fluctuations in the proton beam injection position on the mercury target, temperature/time fluctuations of beam optics components and neutron detectors, and so on. The neutron flux must be influenced by many factors and is practically not easy to predict. In order to ascertain the fluctuation, we have developed a flux monitor detector that combines a flexible optical fiber with a scintillator piece as small as several hundred microns. The detector is the size of the fiber itself and can be installed in a limited space. The fiber tube is very long (20 m), allowing the scintillation light to be carried outside the spectrometer room, facilitating subsequent signal processing. The intensity of the scintillation light due to the small scintillator and long fiber transport was successfully amplified to a waveform with realistically measurable pulse height. The amplifier was tuned for data collection by GateNET, and measurement tests were performed assuming that this detector will be used in the MLF. In the 2024A period, the neutron flux measurements were repeated for several days. While the flux was basically synchronized with the proton beam current, we also confirmed that it showed different behavior. In this presentation, we will introduce the performance of the developed fiber detector, its detection system, and examples of measurements. The actual fiber detector will also be exhibited.

High intensity operation of J-PARC accelerators

Kinsho, Michikazu

no journal, , 

The linac beam commissioning has started in December, 2006, and the RCS beam commissioning in September, 2007. On January 24th, 2007 the linac accelerated the H beam up to the energy of 181 MeV which was the design value, and we accelerated the 181 MeV beam injected from the linac to the designed beam energy of 3 GeV via the RCS, and extracted it to the beam transport (referred to as 3NBT) to the muon and neutron production targets on October 31st, 2007. The beam was delivered for the MLF and the MR for their beam commissioning on May 2008. The user operation for the MLF with beam power of 4 kW was started and also on 25 Hz switching operation for the MLF and the MR December 2008. Since then, the RCS beam power ramp-up has proceeded well. At the beginning of the beam operation, the energy of the linac was 181 MeV. In 2013, the new accelerator structure ACS (Annular-ring Coupled Structure) linac was installed and the 400 MeV injection system was also prepared in the RCS. Then, to achieve higher peak beam current with the linac, the ion source and the RFQ were replaced from 30 mA to 50 mA peak current, and the output beam power of 1 MW from the RCS was prepared. Subsequently, the beam power from the RCS was increased while reducing beam loss, and the beam power for the MLF user operation has been conducted at the designed output beam power of 1 MW since April 2024. In the MR, beam commissioning for slow and fast extraction started in 2008 to increase beam power while reducing beam loss as in the RCS. After repetition upgrade, the beam power of 750 kW, which was the original design beam power, was achieved in December 2023. After that, further beam commissioning has been performed continuously to mitigate beam losses, and now the beam power of 800 kW has been achieved for the Neutrino experiment. As for the slow extraction, beam power has been steadily increased and the beam power of more than 80 kW has been delivered to the Hadron experimental hall this year.

Evaluation of vibration characteristics and construction of control system for fast disc chopper

Komine, Ryota; Kambara, Wataru*

no journal, , 

In MLF at J-PARC, around 30 choppers are used in some neutron beamlines. There are some different kinds of choppers in MLF and they are selected depending on purposes of experiments. These choppers have been operated for more than 10 years and this long-time use causes some problems that seems to be considered as a deterioration over time have occurred. Therefore, we have been exchanging some parts and developing new choppers in recent years. We replaced the conventional fast disc chopper with new one last year. A fast disc chopper cuts out neutron beams from a moderator to shape, and vibration can be a problem. Especially, a resonance is one of the big problems. Once the rotation speed coincides with the resonated point, the chopper vibrates so intensely that it cannot keep the operation stable. To evaluate the resonance problems, a hammering test was done to get vibration characteristics. We evaluated the chopper's vibration characteristics from frequency spectra that can be obtained by FFT analysis. The instrument control software framework "IROHA2" is used for the neutron experiments in MLF and the system can be used through a web browser. We developed device module for the fast disc chopper to acquire the operation data automatically and control instruments remotely. This presentation will describe the outline of the hammering test result and its evaluation, and control system using IROHA2 for the new fast disc chopper.

A Method for site-selective deuteration of amino acids and the development of new biopolymer materials

Shibazaki, Chie; Ueda, Misaki*; Takata, Shinichi; Adachi, Motoyasu*; Akutsu, Kazuhiro*

no journal, ,