Quantitative method for analyzing radioactive nuclides in infinite composite materials using high-resolution. gamma. -ray spectroscopy

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1982

OSTI ID:6156013

Day, Jr, J H

A theory is formulated in which the concentration of a radionuclide uniformly distributed throughout an infinite medium is related to the photopeak count rate of a signature ..gamma.. ray acquired by a detector within the medium. The mass fraction of the i/sup th/ radionuclide in the medium is given by f/sub i/ = W/sub i/psi/sub i/(E)/psi/sub i/I/sub I/(E)K(E); where lambda/sub i/(E) and I/sub i/(E) are the observed photopeak count rate and absolute intensity for a ..gamma..-ray emissions of energy E. lambda/sub i/ and W/sub i/ are the decay constant and isotopic mass, respectively. It is shown that the function K(E) is a source volume integration over epsilon(E,R Vector)B(E,R)exp(-..sigma mu..(E)r(R))/absolute value R/sup 2/ which depends on ..gamma..-ray energy only. Values of the narrow beam attenuation coefficient ..mu.. are known for many materials. However, several laboratory experiments are performed in order to obtain data from which to empirically determine the detector response function epsilon(E,R Vector) and the ..gamma..-ray build-up-factor B(E,R Vector). Special experimental instrumentation for analyzing radionuclides in infinite composite materials using high-resolution ..gamma..-ray spectrometry is introduced. A probe is constructed which contains a coaxial high-purity germanium crystal to detect the ..gamma.. rays, a cryostat to cool the crystal and electronic circuitry to process the signal from the detector. Laboratory models of natural formations are prepared using high-grade radioactive samples diluted with silicon dioxide to obtain the desired concentrations. Each model is sampled to obtain X-ray fluorescence, delayed neutron and fluorimetric analysis from independent laboratories to compare with results using the method presented in this work.

• Research Organization: Howard Univ., Washington, DC (USA)
• OSTI ID: 6156013
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
GAMMA SPECTROMETERS
DESIGN
RADIOISOTOPES
GAMMA SPECTROSCOPY
COMPOSITE MATERIALS
INTERLABORATORY COMPARISONS
MATHEMATICAL MODELS
MEASURING METHODS
QUANTITATIVE CHEMICAL ANALYSIS
CHEMICAL ANALYSIS
ISOTOPES
MATERIALS
MEASURING INSTRUMENTS
SPECTROMETERS
SPECTROSCOPY
400103* - Radiometric & Radiochemical Procedures- (-1987)