Effects of soil moisture on the detection of buried explosives by radiative neutron capture

The effect of soil moisture on the sensitivity for detecting buried landmin es by neutron capture reactions has been experimentally investigated. An ex plosive simulant melamine sample has been placed at different depths in soi l having different water contents. In dry soil it is found that the decreas e of counting rate by increasing the depth follows the decrease of the aver age solid angles. In the case of soil with higher water content, an extra y ield of prompt gamma-rays following: thermal neutron capture in nitrogen is evidenced due to the extra moderation provided by the presence of addition al hydrogen nuclei. (C) 2001 Elsevier Science B.V. All rights reserved.