Simulated Borehole for Ore Depth Evaluation by Neutron Capture gamma-Ray Technique Using Pu/Be Neutron Source

摘要

In this work an attempt was made to study the response as well as the effective depth of a borehole sonde designed and tested for possible in situ ore analysis. A laboratory model to function as a borehole probe for elemental analysis by neutron capture gamma-ray technique, was designed to work both in laboratory and in situ. The borehole sonde consists of an aluminium borehole casing 700 mm deep and 120 mm inner diameter. It contains a 5 Ci, Pu/Be isotopic neutron source, a shadow shield and the Ge(Li) detector. The assembly was designed and constructed for high gamma-ray sensitivity, low interference and minimum radiation damage to the Ge(Li) detector. The depth investigations were done by progressively measuring the neutron capture gamma-spectrum from domestic hematite ore sample at various diameters. Results of the analysis of the prompt gamma-ray spectrum from the hematite ore sample using the described sonde have been presented. The optimum depth at which the sonde is effective and the depth beyond which no significant contribution to the capture gamma-spectrum were determined. (Atomindex citation 17:018422)