الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
N,utron induced prompt y-ray techniques have considerable pootential for measuring elemen-t;.al concen·t.rations of materials in comp] ,( samples and in bulk form. Applications include borehole during exploration, grade control during mining operation and on -line I ani taring in mineral processing. Neut.ron interaction techniques are important because they are unique in possessing elemental speci£ici ty and a degree of pene’tration which is large compared with the wall thickness of containment vessels and adeeqUdte t,o overcome borehole conditions and to allow the interrogaation of surrounding virgin formations. In addition, the range is generally significant, compared with the local elemental heteroogeneity of the mat.erials being analyzed and large compared with the dimensions of particles normally encountered in minerals han-
l’ ng situ tions. Conseql.en tly, these -techniques can provide reppresentative analysis without the need for sampling procedures. It is these aspects of neutron interaction techniques which make them particularly at·trac·tive as the basis of an analytical method worthy of further development.
This thesis is dealing with the design and construction of a borehole Neutron Capture Prompt Gamma Ray Analysis (NCPGRA) simuulator. It consists of a borehole probe surrounded by a cylindriical container to hold the material to be analyzed. The borehole tube is made of a stainless steel casing of 50 cm height and 11
cm diameter. The borehole probe consists of a 5 1.1. g 252 Cf isotopic neutron source of 1.15 x 107 n/sec strength located in the geoometrical center of a paraffin wax cylinder to serve as a neutron moderator. A 81 cm3 High-Puri ty Germanium (BPGe) coaxial photon detector system of 18.4 % relative efficiency at 1.33 MeV, GOCo was used to collect the induced prompt gamma-ray spectra. A shaddow shield consists of lead and lithium carbonate (Li2C03) is being located between the source-moderator assembly and the HPGe crystal. The former is used to shield the detector against gammma-rays \Ihich emitted directly from 252Cf neutron source, while the later is used to shield the HPGe crystal against the probable. damage due to both thermal and fast neutrons. A paraffin wax loaded with boron carbide was made in the form of a jacket lined with 0.1 em cadmium sheet; it was designed to surround the EPGe crystal to serve as an additional shield against both thermal and fast neutrons, which may success to arrive at the detector crysstal.
The development of neutron techniques for the analysis of materials in bulk rests strongly on obtaining an urJderstanding of the relationship between the nature and spatial distribution of neutron interactions and the composition and physical state of the materials to be analyzed. The two neutron energy group diffuusion equation was used to calculate both epithermal and thermal neutron fluxes in the material surrounding the 252Cf-HPGe probe. A good indication of the general behavior of the neutron trans-