NATURAL RADIOACTIVITY OF SAMARIUM AND NEODYMIUM
Thin samples containing about 50 mu gm/cm/sup 2/ of natural samarium, 0.3 mu gm/cm/sup 2/ of natural uranium, and 0.5 mu gm/cm/sup 2/ of elemental boron were analyzed in a grid-type ionization chamber in the presence of a thermal nuclear flux of 1.5 x 10/sup 3/ n/cm/sup 2/ obtained from a polonium- beryllium source. The neutrons absorbed by boron gave rise to alpha particles with energies of 1.797 and 1.474 Mev, respectively, which were recorded photographically together with the samarium and uranium alpha particles for the purposes of calibration. By the use of exposures several days long, spectra containing 10/sup 4/ to 10/sup 5/ pulses were obtained and analysed with a spectrophotometer. The result for the alpha energy of saraarium-147 is E = 2.20 plus or minus 0.03 Mev. The specific activity of samarium147 was measured by counting the alpha particles from 28.9 mgm of samarium which were vacuum- evaporated on a source plate of diameter 200 mm. Taking into account self- absorption and back-scattering, a value of 7.00 plus or minus 0.3 counts/min/ mgm of natural samarium is obtained, which corresponds to a half-life of 1.14 plus or minus 0.05 x 10/sup 11/ yr. for the isotope 147. An attempt to detect the natural alpha activity of neodymium was made using a 200-mm source plate on which 36 mgm of neodymium were evaporated. In spite of appreciable thorium contamination a weak line was observed at 2.0 plus or minus 0.1 Mev., inagreement with investigations made by the emulsion method. (auth)
- Research Organization:
- Univ. of Helsinki
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-14-009430
- OSTI ID:
- 4195082
- Journal Information:
- Nature, Journal Name: Nature Vol. Vol: 185
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
ON THE NATURAL RADIOACTIVITY OF SAMARIUM
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Thu Dec 31 23:00:00 EST 1959
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OSTI ID:4832747
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Journal Article
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OSTI ID:4116131
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Journal Article
·
Tue Oct 01 00:00:00 EDT 1963
· Izvestiya Akademii Nauk, Seriya Fizicheskaya (U.S.S.R.) For English translation see Bull. Acad. Sci. USSR, Phys. Ser. (Engl. Transl.)
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OSTI ID:4108157
Related Subjects
ABSORPTION
ALPHA DETECTION
ALPHA PARTICLES
BACKGROUND
BERYLLIUM
BORON
CHEMISTRY
CONTAMINATION
EMULSIONS
EVAPORATION
HALF-LIFE
IONIZATION CHAMBERS
MEASURED VALUES
NEODYMIUM
NEUTRON DETECTION
NEUTRON FLUX
NEUTRONS
PHOTOGRAPHIC FILM DETECTORS
PHOTOMETRY
PLATES
POLONIUM
RADIATION SOURCES
RADIOACTIVITY
SAMARIUM
SAMARIUM 147
SCATTERING
SPECTRA
THERMAL NEUTRONS
THORIUM
URANIUM
VACUUM
ALPHA DETECTION
ALPHA PARTICLES
BACKGROUND
BERYLLIUM
BORON
CHEMISTRY
CONTAMINATION
EMULSIONS
EVAPORATION
HALF-LIFE
IONIZATION CHAMBERS
MEASURED VALUES
NEODYMIUM
NEUTRON DETECTION
NEUTRON FLUX
NEUTRONS
PHOTOGRAPHIC FILM DETECTORS
PHOTOMETRY
PLATES
POLONIUM
RADIATION SOURCES
RADIOACTIVITY
SAMARIUM
SAMARIUM 147
SCATTERING
SPECTRA
THERMAL NEUTRONS
THORIUM
URANIUM
VACUUM