Determination of Uranium and Thorium in Brazilian coals by epithermal neutron activation analysis
Description
An experimental technique for the determination of uranium and thorium in coal by epithermal neutron activation was developed and systemized. Seventeen different coal samples, six copper monitors for neutron flux corrections and three NBS standard coal samples were irradiated together in a cadmium cylinder. Uranium and thorium were determined by measuring the 239N sub(p) and 233P sub(a) activities respectively, being both produced in (n,γ) reactions and subsequent β- decay. The 239N sub(p) was measured by counting the 106.4 KeV γ-ray in a LEPS detector and the 233P sub(a) by counting the 311.8 KeV γ-ray, but in a Ge(Li) detector. A 4096 multichannel analizer and a PDP-11 computer complemented the basic measuring equipment. An average precision of 3% was obtained in the analysis of seventeen coal samples coming from different strata and heights of Charqueadas and Morungava mines in Rio Grande do Sul State. The sensitivity of the method is around 100 ppb. This technique will allow determinations of up to twenty elements, besides uranium and thorium, and it can be applied in routine analysis. (Author)
Availability note (English)
MF available from INIS under the Report Number.Abstract (Portuguese)
Foi desenvolvida e sistematizada uma tecnica experimental para a determinacao de uranio e torio, em carvoes minerais, utilizando o metodo de analise por ativacao com neutrons epitermicos. Irradiaram-se num cilindro de cadmio, dezessete amostras diferentes de carvao, seis monitores de cobre para corrigir variacoes de fluxo de neutrons e tres amostras de carvao-padrao do 'National Bureau of Standard' dos Estados Unidos. As determinacoes de uranio e torio foram realizadas por medicao das atividades 239N sub(p) e 233P sub(a), respectivamente, e formadas em reacao (n,γ) e subsequente decaimento β-. A medicao do 239N sub(p) foi feita por contagem do raio γ de 106,4 KeV usando-se um detector LEPS e a do 233Pa por contagem do raio γ de 311,8 KeV num detetor Ge(Li). Um analisador de 4096 canais e um computador PDP-11 completaram o equipamento basico de medida. Na analise de dezessete amostras correspondentes a distintas camadas e alturas das Minas Charqueadas e Morungava, do Estado do Rio Grande do Sul, obteve-se uma precisao media de 3% e a sensibilidade do metodo e em torno de 100 ppb. Alem de uranio e torio e possivel analisar mediante esta tecnica ate 20 outros elementos e, pelos resultados obtidos a tecnica podera ser utilizada em analise de rotina. (Autor)Files
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Additional details
Additional titles
- Original title (Portuguese)
- Determinacao de uranio e torio em carvoes minerais brasileiros utilizando analise por ativacao com neutrons epitermicos
Publishing Information
- Imprint Pagination
- 91 p.
- Report number
- INIS-mf--7839
INIS
- Country of Publication
- Brazil
- Country of Input or Organization
- Brazil
- INIS RN
- 14740575
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- ACCURACY; COAL; EPITHERMAL NEUTRONS; LI-DRIFTED GE DETECTORS; MULTI-CHANNEL ANALYZERS; NEUTRON ACTIVATION ANALYSIS; SENSITIVITY; THORIUM; URANIUM
- Descriptors DEC
- ACTINIDES; ACTIVATION ANALYSIS; BARYONS; CARBONACEOUS MATERIALS; CHEMICAL ANALYSIS; ELECTRONIC EQUIPMENT; ELEMENTARY PARTICLES; ELEMENTS; ENERGY SOURCES; EQUIPMENT; FERMIONS; FOSSIL FUELS; FUELS; GE SEMICONDUCTOR DETECTORS; HADRONS; LI-DRIFTED DETECTORS; MATERIALS; MEASURING INSTRUMENTS; METALS; NEUTRONS; NUCLEONS; PULSE ANALYZERS; RADIATION DETECTORS; SEMICONDUCTOR DETECTORS