Jun Kawarabayashi

Progress in development of neutron energy spectrometer for deuterium plasma operation in KSTAR.

Two types of DD neutron energy spectrometer (NES) are under development for deuterium plasma operation in KSTAR to understand behavior of beam ions in the plasma. One is based on the state-of-the-art nuclear emulsion technique. The other is based on a coincidence detection of a recoiled proton and a scattered neutron caused by an elastic scattering of an incident DD neutron, which is called an associated particle coincidence counting-NES. The prototype NES systems were installed at J-port in KSTAR in 2012. During the 2012 and 2013 experimental campaigns, multiple shots-integrated neutron spectra were preliminarily obtained by the nuclear emulsion-based NES system.

A study on fast digital discrimination of neutron and gamma-ray for improvement neutron emission profile measurement

Neutron and γ-ray (n-γ) discrimination with a digital signal processing system has been used to measure the neutron emission profile in magnetic confinement fusion devices. However, a sampling rate must be set low to extend the measurement time because the memory storage is limited. Time jitter decreases a discrimination quality due to a low sampling rate. As described in this paper, a new charge comparison method was developed. Furthermore, automatic n-γ discrimination method was examined using a probabilistic approach. Analysis results were investigated using the figure of merit. Results show that the discrimination quality was improved. Automatic discrimination was applied using the EM algorithm and k-means algorithm.

Construction of 1.7 MV Pelletron Tandem Accelerator System and Its Application to Human Resource Development at Tokyo City University Atomic Energy Research Laboratory

Naoto HAGURA, Noriyosu HAYASHIZAKI, Takafumi UCHIYAMA, Yoshiyuki OGURI, Hitoshi FUKUDA, Katsunori KAWASAKI, Tamotsu TORIYAMA, Koichi MOCHIKI, Yukiko OKADA, Jun KAWARABAYASHI, Ishi MITSUHASHI and Haruaki MATSUURA 1 Department of Nuclear Safety Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557, Japan 2 Atomic Energy Research Laboratory, Tokyo City University, 971 Ozenji, Asao-ku, Kawasaki, 215-0013, Japan 3 Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan 4 Technical Department, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan 5 Electrostatic Accelerator Research Laboratory, 3-1-22-P2-502 Honcho, Higashikurume-city, Tokyo 203-0053, Japan 6 Laboratory for Materials Engineering with Quantum Beams, 4-2-17 Nishigahara, Kita-ku, Tokyo 114-0024, Japan

Improvement of spatial resolution of time-resolved MA-PMT camera for imaging of TRU elements

The use of alpha autoradiography is ineffective for measuring plutonium (Pu) spots in a transuranic element containing alpha-radiator minor actinides. Therefore, the KURRI-LINAC team, Kyoto University has developed a non-destructive imaging system with pulsed neutron transmission spectroscopy. The system uses a high-efficiency bundle-type scintillator and a 16 × 16 ch multi-anode photo-multiplier tube (MA-PMT) and Li-Time-Analyzer-12e (LiTA12e) processor as detector. The spatial resolution of this system was improved by 3 mm of MA-PMT to 1 mm of the scintillator by the center-of-gravity calculation of the LiTA12e system. However, a 1-mm spatial resolution is insufficient to detect the Pu spot of one of the TRU elements using the program. Therefore, we are developing a super-resolution technique with sub-pixel shifted images for the transmission images. The calculated reconstructed image, based on the use of four sub-pixel shifted X-ray transfer images, was obtained by simulation. This result suggests the spatial resolution of the imaging system will be improved by installing stepping motors in the platform of a measurement object.

Development of resonance neutron imaging based on glass-GEM

A resonance neutron imaging system has been developed based on combination of a glass based Gas Electron Multiplier (Glass GEM) detector and a resonance filter. This system has the capability of imaging the neutron spatial distribution in energy of resonance peaks corresponding to a resonance filter. A clear dip corresponding to a resonance peak of 109Ag (4.2~6.3 eV) was confirmed in measured response function. In addition, expected system performance was investigated by Monte Carlo simulation based on Particle and Heavy Ion Transport code System (PHITS) for application to resonance neutron radiography.