Boron determination in tourmaline by neutron induced radiography

The technique of neutron induced radiography has been applied to determine the boron concentration and its spatial distribution in mineral tourmaline collected from Swat Tourmaline Granite, Northern Pakistan. The technique in volves the simultaneous irradiation of sample and a standard fixed on a tra ck detector with thermal neutrons and the counting of alpha and Li-7 tracks produced in the detector from the nuclear reaction B-10(n,alpha)Li-7. Boro n concentration is determined by comparing the Li-7 and alpha particle trac ks density with that of a standard of known boron concentration. Boron conc entration in tourmaline has been found to be (3.40 +/- 0.01)% in this study which is on the upper side within the normal range (2.5-3.8)% reported in the world. The presence of somewhat higher concentration of boron in tourma line indicates that the Swat Tourmaline Granite was generated as a late sta ge hydrothermal activity during the Himalayan Orogeny. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.