Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays

Conference · Mon Dec 31 23:00:00 EST 1990 · Nuclear Materials Management. Annual Meeting Proceedings; (United States)

OSTI ID:5587282

Parker, J L ^[1]

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1. Los Alamos National Lab., NM (United States)

This paper reports that both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry spectra from uranium oxide standards whose enrichments ranged from 0.7% to 91%, relative values, primarily, have been obtained for the probabilities of both processes. Thorium x-ray emission is very heavily dominated by {sup 235}U. In all ordinarily occurring uranium isotopic distributions, thorium x-rays may be used as a valid {sup 235}U signature. The probability for a thorium K{sub {alpha}1} x-ray to be emitted in the decay of a {sup 235}U atom is 0.048 {plus minus} 0.002. In infinitely thick uranium oxide materials, the relative ratios of effectiveness for self-fluorescence, on a per unit mass basis, are approximately {sup 234}U : {sup 235}U : {sup 236}U : {sup 238}U = 1.13 : 1.00 : 0.52 : 0.028. On a per decay basis, the approximate ratios are 0.00039 : 1.00 : 0.017 : 0.18. These results imply that, contrary to what has often been stated, gamma rays are far more important than alpha particles in the self-fluorescence of uranium. Because of the importance of gamma-ray self-fluorescence, the uranium x-ray yield will be somewhat influenced by the size, shape, and composition of the materials.

• OSTI ID: 5587282
• Report Number(s): CONF-910774--
• Journal Information: Nuclear Materials Management. Annual Meeting Proceedings; (United States), Journal Name: Nuclear Materials Management. Annual Meeting Proceedings; (United States) Vol. 20; ISSN NUMMB; ISSN 0362-0034
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
220600* -- Nuclear Reactor Technology-- Research
Test & Experimental Reactors
440103 -- Radiation Instrumentation-- Nuclear Spectroscopic Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ACTINIDE ISO
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ACTINIDES
ALPHA DECAY RADIOISOTOPES
ALPHA PARTICLES
CHARGED PARTICLES
ELEMENTS
EMISSION SPECTRA
ENERGY SOURCES
ENRICHMENT
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUORESCENCE
FUELS
GAMMA SPECTRA
HEAVY ION DECAY RADIOISOTOPES
HEAVY NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LUMINESCENCE
MAGNESIUM 28 DECAY RADIOISOTOPES
MATERIALS
METALS
MINUTES LIVING RADIOISOTOPES
NEON 24 DECAY RADIOISOTOPES
NUCLEAR FUELS
NUCLEI
PROBABILITY
RADIOISOTOPES
REACTOR MATERIALS
RESOLUTION
SPECTRA
SPENT FUELS
SPONTANEOUS FISSION RADIOISOTOPES
THORIUM
URANIUM
URANIUM 234
URANIUM 235
URANIUM 236
URANIUM 238
URANIUM ISOTOPES
X-RAY SPECTRA
YEARS LIVING RADIOISOTOPES
YIELDS