Speaker
Dr
Kentaro Toh
(Japan Atomic Energy Agency)
Description
Some neutron scattering experiments performed at high-intensity pulsed neutron facilities located in Japan, the United States, and the United Kingdom require advanced two-dimensional neutron detectors that have features such as a short response time, good spatial resolution, and high detection efficiency. To this end, we are currently developing a two-dimensional position-sensitive neutron detection system that can read out individual signal lines and consists of a micro-pixel detector element. By increasing the gas pressure, the spatial resolution and detection efficiency of a two-dimensional gas-based detector are improved but the output signal strength is decreased. Therefore, the supply voltage must be increased to obtain output signals under high pressure. In the present study, we have developed a micro-pixel detector element with a high-voltage resistance by an improved fabrication process, and then, we have conducted neutron irradiation experiments using this detector element. A detection system capable of individual line readout and consisting of the developed detector element, a pressure vessel, amplifier-shaper-discriminator boards, an optical signal transmission device, and a fast data acquisition device was constructed for the experiment. The voltage resistance of the developed element was improved, and the element could operate up to 750 V at a total pressure of 5 atm (4.1 atm of He for the neutron converter and 0.9 atm of CF4 for the stopping gas). The measured gas gain was found to be approximately 100, and the thermal neutron detection efficiency was estimated to be 70% at the gas pressure of 5 atm. A flat-field image was obtained to confirm the spatial homogeneity of the detector element. The image showed good homogeneity, and the average pixel count was 290 with a standard deviation of σ = 25.4, corresponding to an average gain spread of about 8.7%.
Preferred medium (Oral/poster)
poster
Author
Dr
Kentaro Toh
(Japan Atomic Energy Agency)
Co-authors
Dr
Hideshi Yamagishi
(Japan Atomic Energy Agency)
Dr
Kaoru Sakasai
(Japan Atomic Energy Agency)
Dr
Kazuhiko Soyama
(Japan Atomic Energy Agency)
Dr
Tatsuya Nakamura
(Japan Atomic Energy Agency)
