Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and i...Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.展开更多
In order to calculate absolute efficiency of the BF3 detector, MCNP/4C code is applied to calculate relative efficiency of the BF3 detector first, and then absolute efficiency is figured out through mathematical techn...In order to calculate absolute efficiency of the BF3 detector, MCNP/4C code is applied to calculate relative efficiency of the BF3 detector first, and then absolute efficiency is figured out through mathematical techniques. Finally an energy response curve of the BF3 detector for 1~20 MeV neutrons is derived. It turns out that efficiency of BF3 detector are relatively uniform for 2~16 MeV neutrons.展开更多
The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably.In this work an ^(241)Am-Be source was used in the moderator geometry for detecting buri...The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably.In this work an ^(241)Am-Be source was used in the moderator geometry for detecting buried landmines by PGNAA method.Experiments were done to find the best moderator geometry for the moderated ^(241)Am-Be source,by replacing the mine with a neutron detector and counting the thermal neutron flux.The flux of thermal neutrons at the place of mine was used as a determining factor to introduce the best moderator geometry.展开更多
Thermal neutron albedo has been investigated for different thicknesses of mono-material and bi-material reflectors. An equation has been obtained for a bi-material reflector by considering the neutron diffusion equati...Thermal neutron albedo has been investigated for different thicknesses of mono-material and bi-material reflectors. An equation has been obtained for a bi-material reflector by considering the neutron diffusion equation. The bi-material reflector consists of binary combinations of water, graphite, lead, and polyethylene. An experimental measurement of thermal neutron albedo has also been conducted for mono-material and bi-material reflectors by using a^(241) Am–Be(5.2 Ci) neutron source and a BF3 detector. The maximum value of thermal neutron albedo was obtained for a polyethylene–water combination(0.95 ± 0.02).展开更多
文摘Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.
文摘In order to calculate absolute efficiency of the BF3 detector, MCNP/4C code is applied to calculate relative efficiency of the BF3 detector first, and then absolute efficiency is figured out through mathematical techniques. Finally an energy response curve of the BF3 detector for 1~20 MeV neutrons is derived. It turns out that efficiency of BF3 detector are relatively uniform for 2~16 MeV neutrons.
文摘The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably.In this work an ^(241)Am-Be source was used in the moderator geometry for detecting buried landmines by PGNAA method.Experiments were done to find the best moderator geometry for the moderated ^(241)Am-Be source,by replacing the mine with a neutron detector and counting the thermal neutron flux.The flux of thermal neutrons at the place of mine was used as a determining factor to introduce the best moderator geometry.
文摘Thermal neutron albedo has been investigated for different thicknesses of mono-material and bi-material reflectors. An equation has been obtained for a bi-material reflector by considering the neutron diffusion equation. The bi-material reflector consists of binary combinations of water, graphite, lead, and polyethylene. An experimental measurement of thermal neutron albedo has also been conducted for mono-material and bi-material reflectors by using a^(241) Am–Be(5.2 Ci) neutron source and a BF3 detector. The maximum value of thermal neutron albedo was obtained for a polyethylene–water combination(0.95 ± 0.02).
