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Title: RADIOCARBON FROM PILE GRAPHITE CHEMICAL METHODS FOR ITS CONCENTRATIONS

Abstract

Samples of pile graphite, irradiated in a test-hole at Hanford for 15 months, have been assayed for radioactive C{sup14}, yielding 0.38 ± 0.04 microcuries per gram. At this level of activity, the pile graphite contains very valuable amounts of C{sup14}. The relation between the above assay and the probable average assay of pile graphite is discussed, and it is concluded that the latter is almost certainly above 0.3 uc/ gram. Controlled oxidation of this graphite, either with oxygen at ~ 750°C, or with chromic acid "cleaning solution" at room temperature, yields early fractions which are highly enriched in C{sup14}. Concentrations of 5-fold with oxygen, and 50-fold with CRO{sub3}, have been observed. The relation between the observed enrichment and the Wigner effect is discussed, and a mechanism accounting for the observations put forward. According to this, about 25% of the stable carbon atoms in the lattice have been displaced by Wigner effect, a large fraction of which have healed the migrating to crystal edges. All the C{sup14} atoms have been displaced, and the same fraction of these migrate to the edges. The enrichment then results from surface oxidation, in the oxygen case. Predictions are made on the basis of this hypothesis.more » A technique of counting radioactive CO{sub2} in the gas phase is described.« less

Authors:
;
Publication Date:
Research Org.:
Argonne National Lab., Lemont, Ill.
Sponsoring Org.:
US Atomic Energy Commission (AEC)
OSTI Identifier:
4350390
Report Number(s):
CC-3643
NSA Number:
NSA-11-008308
DOE Contract Number:  
W-31-109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: Decl. Feb. 16, 1957. Orig. Receipt Date: 31-DEC-57
Country of Publication:
United States
Language:
English
Subject:
CHEMISTRY; CARBON 14; CARBON DIOXIDE; CHROMIUM OXIDES; CONTROL; COUNTERS; DIFFUSION; ENRICHMENT; GASES; GRAPHITE; IRRADIATION; LABELLED COMPOUNDS; MEASURED VALUES; OXIDATION; OXYGEN; QUALITATIVE ANALYSIS; RADIATIONS; REACTORS; SURFACES; WIGNER EFFECT

Citation Formats

Arnold, J.R., and Libby, W.F.. RADIOCARBON FROM PILE GRAPHITE CHEMICAL METHODS FOR ITS CONCENTRATIONS. United States: N. p., 1946. Web. doi:10.2172/4350390.
Arnold, J.R., & Libby, W.F.. RADIOCARBON FROM PILE GRAPHITE CHEMICAL METHODS FOR ITS CONCENTRATIONS. United States. doi:10.2172/4350390.
Arnold, J.R., and Libby, W.F.. Thu . "RADIOCARBON FROM PILE GRAPHITE CHEMICAL METHODS FOR ITS CONCENTRATIONS". United States. doi:10.2172/4350390. https://www.osti.gov/servlets/purl/4350390.
@article{osti_4350390,
title = {RADIOCARBON FROM PILE GRAPHITE CHEMICAL METHODS FOR ITS CONCENTRATIONS},
author = {Arnold, J.R. and Libby, W.F.},
abstractNote = {Samples of pile graphite, irradiated in a test-hole at Hanford for 15 months, have been assayed for radioactive C{sup14}, yielding 0.38 ± 0.04 microcuries per gram. At this level of activity, the pile graphite contains very valuable amounts of C{sup14}. The relation between the above assay and the probable average assay of pile graphite is discussed, and it is concluded that the latter is almost certainly above 0.3 uc/ gram. Controlled oxidation of this graphite, either with oxygen at ~ 750°C, or with chromic acid "cleaning solution" at room temperature, yields early fractions which are highly enriched in C{sup14}. Concentrations of 5-fold with oxygen, and 50-fold with CRO{sub3}, have been observed. The relation between the observed enrichment and the Wigner effect is discussed, and a mechanism accounting for the observations put forward. According to this, about 25% of the stable carbon atoms in the lattice have been displaced by Wigner effect, a large fraction of which have healed the migrating to crystal edges. All the C{sup14} atoms have been displaced, and the same fraction of these migrate to the edges. The enrichment then results from surface oxidation, in the oxygen case. Predictions are made on the basis of this hypothesis. A technique of counting radioactive CO{sub2} in the gas phase is described.},
doi = {10.2172/4350390},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Oct 10 00:00:00 EST 1946},
month = {Thu Oct 10 00:00:00 EST 1946}
}

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