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Characterization of the Schlumberger borehole gammametric system

Abstract

The expertise and equipment for {gamma}-ray spectroscopy at the Nuclear Beam Technology group at Pelindaba was used to characterise a Schlumberger NaI{gamma}-ray detector. The detector is fitted in a drilling housing; and can be lowered down boreholes to trace radioactive or activated elements. This detector is specifically used for prospecting purposes, studying the {gamma}-rays that accompany the presence of mining minerals. The problem of inconsistent results at high count rates was characterised, and the shift in amplifier gain was determined as a function of total count rate. The performance of the software to strip the elements of the spectrum was also checked and found to fail at count rates of 20 kHz and higher. The stabilisation circuit was found to become less effective already at moderate count rates ({approx_equal} 5kHz). The experiment was performed by comparing the count rate in five energy windows between the Schlumberger {gamma}-ray detector and a Ge(Li) solid state {gamma}-ray detector, where the lower efficiency and detection characteristics of this detector provided a reliable reference. The problem was largely solved by introducing lead shielding to allow the unit to stabilise itself more effectively at high count rates. With the addition of 3 mm lead shielding, the  More>>
Publication Date:
Feb 01, 1991
Product Type:
Technical Report
Report Number:
PEL-306
Reference Number:
SCA: 440103; PA: AIX-23:037006; SN: 92000726238
Resource Relation:
Other Information: PBD: Feb 1991
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; NAI DETECTORS; BOREHOLES; GAMMA DETECTION; AMPLIFIERS; GAIN; GAMMA SPECTROSCOPY; GERMANIUM; LEAD; LITHIUM; POTASSIUM 40; SHIELDING; SOUTH AFRICAN ORGANIZATIONS; STABILITY; THORIUM 232; URANIUM 238; 440103; NUCLEAR SPECTROSCOPIC INSTRUMENTATION
OSTI ID:
10139832
Research Organizations:
Atomic Energy Corp. of South Africa (Pty) Ltd., Pretoria (South Africa)
Country of Origin:
South Africa
Language:
English
Other Identifying Numbers:
Other: ON: DE92626985; ISBN 0 86960 885 1; TRN: ZA9200027037006
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
INIS
Size:
19 p.
Announcement Date:
Jul 05, 2005

Citation Formats

Prozesky, V M, and Franklin, C B. Characterization of the Schlumberger borehole gammametric system. South Africa: N. p., 1991. Web.
Prozesky, V M, & Franklin, C B. Characterization of the Schlumberger borehole gammametric system. South Africa.
Prozesky, V M, and Franklin, C B. 1991. "Characterization of the Schlumberger borehole gammametric system." South Africa.
@misc{etde_10139832,
title = {Characterization of the Schlumberger borehole gammametric system}
author = {Prozesky, V M, and Franklin, C B}
abstractNote = {The expertise and equipment for {gamma}-ray spectroscopy at the Nuclear Beam Technology group at Pelindaba was used to characterise a Schlumberger NaI{gamma}-ray detector. The detector is fitted in a drilling housing; and can be lowered down boreholes to trace radioactive or activated elements. This detector is specifically used for prospecting purposes, studying the {gamma}-rays that accompany the presence of mining minerals. The problem of inconsistent results at high count rates was characterised, and the shift in amplifier gain was determined as a function of total count rate. The performance of the software to strip the elements of the spectrum was also checked and found to fail at count rates of 20 kHz and higher. The stabilisation circuit was found to become less effective already at moderate count rates ({approx_equal} 5kHz). The experiment was performed by comparing the count rate in five energy windows between the Schlumberger {gamma}-ray detector and a Ge(Li) solid state {gamma}-ray detector, where the lower efficiency and detection characteristics of this detector provided a reliable reference. The problem was largely solved by introducing lead shielding to allow the unit to stabilise itself more effectively at high count rates. With the addition of 3 mm lead shielding, the acceptable count rate was improved by a factor 2. 8 figs., 1 tab., 4 refs.}
place = {South Africa}
year = {1991}
month = {Feb}
}