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Kajimoto, Ryoichi; Nakamura, Mitsutaka; Iida, Kazuki*; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Inamura, Yasuhiro; Ishikado, Motoyuki*
Journal of Neutron Research, 22(2-3), p.99 - 107, 2020/10
Sakai, Kenji; Oi, Motoki; Teshigawara, Makoto; Naoe, Takashi; Haga, Katsuhiro; Watanabe, Akihiko*
Journal of Neutron Research, 22(2-3), p.337 - 343, 2020/10
For operating a spallation neutron source and a muon target safely and efficiently, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation and interlock processes of many instruments under various operation status. Since the first beam injection in 2008, it has operated stably without any serious troubles for more than ten years. GCS has a data storage server storing operational data on status around target stations. It has functioned well to detect and investigate unusual situations by checking data in this server. For continuing stable operation of MLF in future, however, introduction of abnormality sign determination system (ASDS) will be necessary for picking up potential abnormalities of target stations caused by radiation damages, time-related deterioration and so on. It will judge abnormalities from slight state transitions of target stations based on analysis with various operational data throughout proton beams, target stations, and secondary beams during long-term operations. This report mentions present status of GCS, conceptual design of ASDS, and installation of an integral data storage server which can deal with various data for ASDS integrally.
Nakajima, Kenji; Kawamura, Seiko; Kofu, Maiko; Murai, Naoki; Inamura, Yasuhiro; Kikuchi, Tatsuya*; Wakai, Daisuke*
no journal, ,
Inamura, Yasuhiro; Yasu, Yoshiji*; Oshita, Hidetoshi*; Nakatani, Takeshi
no journal, ,
One of the recent successful developments in the computing group in MLF at J-PARC is about the "quasi-real-time" data reduction and visualization method, named a live data reduction. From the beginning of MLF running, users have strongly required to see the current data during the measurement to decide next experimental conditions and schedules. To realize "real-time" in these years, we decided to adopt a Publisher-Subscriber model using this technology and developed new modules working on our data acquisition system, DAQ middleware, which sends event-recorded data to a message queue server as a data publisher. In addition, we have a plan to offer users the new methods to obtain speedily the result of the live data reduction for the current measuring data. We start to develop a new server cooperating with the DAQ middleware and the measurement control system with web user interface, called IROHA2, to execute the live data reduction code prepared by users and visualize the result which enables users to confirm them on web browser.
Shibata, Kaoru
no journal, ,
The silicon crystal analyzer is an important spectroscopic device for high energy resolution neutron inelastic backscattering spectrometer. Specification of this spectroscopic device is thought to determine energy resolution and background. In order to achieve a low background spectrum without degradation of the energy resolution, it was developed new crystal analyzer which were constracted by Si wafers coated by thin film of neutron absorbers on the back side of Si wafer, and used it for the new backscattering spectrometer DNA in MLF at J-PARC which were able to achieve the desired performance.
Kamiya, Junichiro; Hasegawa, Kazuo; Kinsho, Michikazu; Oguri, Hidetomo; Yamamoto, Kazami
no journal, ,
In J-PARC, the beam with a power of 500 kW has been stably provided to the MLF for the past year. High availability of 94% during the MLF user operation was achieved in the fiscal year of 2018. Many efforts to reduce downtime causes have been performed such as rejection of undesirable large signals of the beam loss monitors by optimizing a time constant in the circuit, and stabilization of DTL operation of DTL by the cavity cleaning, etc. In addition, trial operations at 1 MW were recently achieved. The accelerator group has begun to consider upgrades for the future operation with more than 1 MW beam power, such as an improvement of the Medium Energy Beam Transport 1 (MEBT1) for optimal beam matching, a reinforcement of the RF system in the RCS, and so on. In this presentation, summary of the current status and upgrade plans for higher beam power operation of the Linac and the RCS will be described.
Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Kawakita, Yukinobu; Matsuura, Masato*; Endo, Hitoshi*; Seto, Hideki*; Ito, Shinichi*; Nakajima, Kenji; Kawamura, Seiko
no journal, ,
Nakamura, Mitsutaka; Kajimoto, Ryoichi; Oikawa, Kenichi; Shinohara, Takenao; Aizawa, Kazuya; Harjo, S.; Iwahashi, Takaaki*; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; et al.
no journal, ,
We have introduced a new Fermi chopper with compact slit package into the direct geometry neutron spectrometer 4SEASONS in Materials and Life Science Experimental Facility at J-PARC, and succeeded in significantly improving the beam intensity compared to the old model. On the other hand, the new Fermi chopper causes an unexpected intensity tail, which may adversely affects the data analysis. In order to solve this problem, we have proceeded with various inspections of a Fermi chopper blade such as Monte Carlo simulation, neutron transmission spectrum measurement and direct observation with a microscope. In this presentation, we will show some approaches taken to solve the problem and explain the rationale that led to the plausible assumption.