ON THE IMAGING OF LAND MINES USING E(-E(-) PAIR PRODUCTION())

The problem of disposing of abandoned land mines is very serious in ma ny countries. And-personnel land mines (APM's) contain as little its 5 0 gram or less of explosive, which is enough to take off an adult's fo ot, or to kill a child. Anti-tank mines (ATM's), designed to penetrate the armour on the bottom of a tank, are much larger. Current techniqu es of finding them are not adequate. All practical high explosives con tain 20% or more of nitrogen, which has a thermal neutron cross sectio n of 75 mbarn, producing gamma's of up to 10.8 MeV. The idea of using this property to detect explosives has been tested by others, but beca use of backgrounds is unable to find anything less than several hundre d grams of explosive. The refinement proposed here is to convert the g amma s, track the resulting e(+) - e(-) pairs in MWPC's, and use the i nformation to locate the gamma source, i.e. the mine. The directional information provided should reduce the backgrounds considerably. Resul t of an experimental test are presented and possibilities for the futu re discussed.