Development of Landmine Detection System Using Scintillators by Measuring Radiations from Landmine

We are trying to establish a landmine detection system by combining the D-D fusion neutron source. The principle idea of the presently developing system is based on the detection of capture gamma-rays from explosive. We are focusing on the detection of 2.22 MeV and 10.83 MeV capture gamma-rays from hydrogen and nitrogen, respectively, since all explosive contain these elements. To detect 10.83 MeV capture gamma-rays, the main detector is employed a BGO scintillator, which is surrounded by annular shaped NaI(T1) scintillator with a hole of 1' in diameter to facilitate the use of anti-coincidence technique to suppress backgrounds and coincidence technique to detect 511 keV escape gamma-rays. To use anti-coincidence technique and coincidence technique, the dual MCA circuit is employed. To examine the performance of this anti-coincidence technique, a preliminary experiment was carried out by using a 60 Co gamma-ray source, and it was found that background level of gamma-rays is suppressed. And to examine the performance of this coincidence technique, melamine was irradiated by 252 Cf neutron source, and the counts of 10.83 MeV region was increased by 27% than previous system of NIM modules by using only anticoincidence technique. On the basis of these experimental results, a series of experiments by combining with the D-D neutron source was conducted. It was found that the capture gamma-rays of 10.83 MeV from nitrogen could be detected clearly.