Authors:Y. Toh, M. Oshima, K. Furutaka, A. Kimura, M. Koizumi, Y. Hatsukawa, and J. Goto
A neutron beam line for multiple prompt gamma-ray analysis was constructed at the Japan Atomic Energy Agency. A detector system
for the MPGA was constructed at the C2-3-2 beam line in January 2005. It comprised eight (upgraded in March 2007) clover Ge
detectors with a BGO Compton suppressor. High efficiency detector system provides an advantage in terms of the detection limit
of MPGA when compared to the result of PGA. The supermirror neutron bender was improved and a supermirror neutron guide was
installed upstream of the sample position.
Authors:Y. Hatsukawa, Y. Toh, M. Oshima, T. Hayakawa, N. Shinohara, K. Kushita, T. Ueno, and K. Toyoda
Multiparameter coincidence g-ray spectrometry based on g-g coincidence is widely used in the field of nuclear structure studies, and has produced many succesful results. In this paper, feasibility of the method for neutron activation analysis of trace elements was studied. Particularly, a long-lived radioisotope 129I (T1/2 = 1.57.107 y) in algae samples and iridium in geological samples has been determined.
Authors:Y. Toh, M. Koizumi, M. Oshima, A. Kimura, Y. Hatsukawa, A. Osa, and J. Goto
In order to improve the sensitivity for the quantification of trace elements, we propose the combination of prompt gamma-ray
analysis (PGA) and a multiple gamma-ray detection method. A new Ge detector system for multiple prompt gamma-ray analysis
(MPGA) was constructed at the neutron guide-hall of the JRR-3M reactor of the Japan Atomic Energy Agency (JAEA). The first
demonstration of this system was given with a plastic sample containing traces of cadmium. The quantification limit of cadmium
in a plastic sample was found to be about 0.1 ppm.
Authors:M. Oshima, Y. Toh, Y. Hatsukawa, M. Koizumi, A. Kimura, A. Haraga, M. Ebihara, and K. Sushida
A new radionuclide quantification method is proposed on the basis of multiple gamma-ray detection, which is two or higher
fold gamma-ray coincidence method. The coincidence method has so far been used for nuclear structure study. We apply this
method for quantification of radioactive nuclei. The advantage of this method consists of high energy resolution and high
sensitivity. It is successfully applied to nuclear waste analysis, neutron activation analysis and prompt gamma-ray analysis.
The principle of the multiple gamma-ray detection method and future perspectives for an innovative pulsed neutron source and
a new detector system will be presented.
Authors:Y. Oura, R. Watanabe, M. Ebihara, Y. Murakami, Y. Toh, A. Kimura, M. Koizumi, K. Furutaka, M. Oshima, K. Hara, T. Kin, S. Nakamura, and H. Harada
A prompt gamma-ray analysis system using multiple detection method (MPGA system) was constructed at the neutron guide hall
of the JRR-3M reactor of the Japan Atomic Energy Agency. We applied MPGA method to geochemical and cosmochemical samples to
evaluate its analytical performance on signal to noise (S/N) ratio, sensitivity, and detection limit. The S/N ratio measured
by MPGA system was larger than that by normal prompt gamma ray activation analysis (PGAA) at JRR-3M. For some elements, the
S/N ratio was improved more than ten times. Several elements that are not detected by PGAA were detected by MPGA. At the present
time, concentrations of major elements and trace elements with high neutron capture cross section in geochemical and cosmochemical
samples were determined accurately by the MPGA system installed at JRR-3M. It is expected that it will determine a lot of
trace elements after appropriate adjustments and modifications.