Sep 3 – 8, 2017
The Open University, Milton Keynes, UK.
Europe/London timezone

Development of a bump cathode element for two-dimensional neutron detection

Sep 7, 2017, 12:40 PM
1h 50m
Hub Theatre (OU)

Hub Theatre (OU)

The Open University, Walton Hall, Milton Keynes, MK7 6AA


Kentaro Toh (Japan Atomic Energy Agency)


A neutron detection element consisting of circular cathode bumps was developed for two-dimensional neutron measurement, and an irradiation experiment was performed using a Cf-252 neutron source. The element has triangularly arranged small-sized circular cathode bumps, and the bumps are linked together in x- and y-directions for the detection of incident neutrons. The sensitive area was 128 × 128 mm2 with a pitch of 1 mm in both directions. The bump cathodes act as a collector of the charged signal arisen from a nuclear reaction between neutron and He-3. Preliminary irradiation experiments for the developed element were performed using a neutron detection system consisting of a pressure vessel, amplifier-shaper-discriminator boards, optical signal transmission devices, position encoders with field-programmable gate arrays, and a data acquisition device. The 256 signal lines (x: 128 lines, y: 128 lines) are individually readout by signal-processing electronics. The element was arranged in the pressure vessel with a fill gas of composition He/(15%)CF4 at 0.7 MPa. Neutron irradiation was performed by embedding a Cf-252 neutron source with an intensity of 100 MBq in a graphite cube with dimensions of 80 cm. The detector system exhibited a one-dimensional uniformity of response of 2.5% and 5.3% in the x- and y-directions, respectively. The uniformity of all pixels in the two-dimensional image was 10.1%. The average intrinsic spatial resolution was 1.9 mm full width at half maximum in the sensitive region calculated by taking into account the track lengths of secondary particles.

Primary author

Kentaro Toh (Japan Atomic Energy Agency)


Tatsuya Nakamura (Japan Atomic Energy Agency) Kaoru Sakasai (Japan Atomic Energy Agency) Hideshi Yanagishi (Nippon Advanced Technology)

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