Abstract:

In January 2003, the Egyptian Atomic Energy Authority has initiated a TC project, EGY01024 with the IAEA to develop and adopt nuclear technologies for landmine detection. Through this TC project and collaboration with the University of Delft in the Netherlands a landmine detection system based on measuring thermal neutrons back scattered from objects hidden in the ground has been developed and installed. The system consists of sixteen position sensitive thermal neutron ³He proportional counter tubes (100 cm length and 2.5 cm diameter) placed in an aluminium tray of 140 cm length, 77 cm width and of 6 cm height. The tubes are covered from the sides and top by Cd sheet of 1 mm thick. The sixteen counter tubes are divided in two groups separated by 15 cm where the neutron source/sources are fixed. Graphite reflectors and shadow steel bars were designed to enhance the neutron flux incident towards the ground and to assure to some extent the same incident flux intensity along the detector tube axis. The detector tray is mounted on a platform fixed at the front of a trolley driven by electric motor and electric control unit. The trolley can move by velocities varying from 5 cm/s to 50 cm/s. The detector platform is provided by two electric motors, one to move the detectors along the side direction and the other to change the stand off distance.

The strength and weakness of the system are checked for the cases where one neutron source and two neutron sources are used. For measurements with one neutron source the source is fixed at the centre of space between the two detector groups while for the two neutron sources are fixed at 40 cm distance apart between the two detector groups. The effectiveness of the system for detecting landmines is checked for land mines with different amount of explosive buried at different depths in the ground.