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Title: NUCLEAR DECAY SCHEME STUDIES ON SHORT-LIVED NUCLIDES FROM THE (n,$gamma$) AND (n, FISSION) REACTIONS

Abstract

A study was made of nuclear decay schemes, primarily of short-lived nuclides, utilizing the irradiation facilities of the Ford Nuclear Reactor at the University of Michigan. Multichannel pulse-height analysis was applied to the study of short-lived fission products and to a search for unreported isomeric transitions among the (n, gamma ) reaction products. Irradiation and handling techniques were developed and instrumental modifications made to facilitate the study of short-lived nuclides. The neutron flux and flux distribution at the irradiation position were measured. A simple and rapid separation of gaseous fission products into krypton and xenon fractions was developed. The primary gamma energies of 3.2-min Kr/sup 89/, 33 sec Kr/sup 90/, 1.2min Rb/sup 91m/, 41- sec Xe/sup 139/, and 66-sec Cs/sup 140/ we re determined and relative gamma intensities measured. Maximum beta energy end-points were measured for Kr/sup 89/ , Kr/sup 90/, Xe/sup 139/ s, Cs/sup 140/, and 9.5 min Cs/sup 139/, and lower limits established f or the decay energies of these nuclides. The gamma rays of the daughter activities, 14.9-min Rb/sup 89/, 2.7-min Rb/sup 90/, and Cs/sup 139/ , previously reported in the literature were verified. An upper limit of 2 minutes was established for the halflife of themore » fission product, Rh/sup 109/, by devising a chemical separation, requiring 6 min, giving decontamination factors of > 10/sup 5/ from other elements. An isomeric level of Pt/sup 199/ was detected and characterized by the (n, gamma ) reaction on normal and enriched platinum samples. The isomer decayed with a half-life of 14.1 plus or minus 0.3 sec by emission of gamma rays of 32 plus or minus 2 kev and 393 plus or minus 2 kev energy. The thermal neutron cross-section for the formation of the isomer was 28 plus or minus 3 mb. A long-lived isomer of Ag/sup 108/ was detected in Ag/sup 110//sup m/ tracer sources sufficiently old that the masking 270 day Ag/sup 110//sup m/ had decayed out. The half-life of the isomer was found to be > 5 years. 90% of the disintegrations proceeded by electron capture followed by a cascade of three gamma rays of 434-, 616-, and 722-kev energy, and 10% went by isomeric transition to 2.4-min Ag/sup 108/. New values were determined for the branching ratios in 2.4-min Ag/sup 108/. No unreported isomeric transitions, with half-lives in the range of 1 sec to 10 min, were detected in the (n, gamma ) reaction on ruthenium, palladium, mercury, rhenium, barium, lanthanum, cerium, praseodymium, samarium, europium, gadohinium, terbium, holmium, erbiu, thulium, ytterbium, or lutetium. (auth)« less

Authors:
Publication Date:
Research Org.:
Michigan. Univ., Ann Arbor
OSTI Identifier:
4016698
Report Number(s):
TID-11807
NSA Number:
NSA-15-025459
DOE Contract Number:  
AT(11-1)-70
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-61
Country of Publication:
United States
Language:
English
Subject:
PHYSICS; BETA DECAY; BETA SPECTROMETERS; CESIUM 139; CESIUM 140; CONFIGURATION; DECAY; ENERGY; FISSION; FISSION PRODUCTS; FORD NUCLEAR REACTOR; GAMMA RADIATION; GASES; HALF-LIFE; INSTRUMENTS; ISOMERS; KRYPTON; KRYPTON 89; KRYPTON 90; MEASURED VALUES; NEUTRON BEAMS; NEUTRON FLUX; NUCLEAR MODELS; NUCLEAR REACTIONS; NUCLEI; PULSE ANALYZERS; REACTORS; RUBIDIUM 89; RUBIDIUM 90; RUBIDIUM 91; SEPARATION PROCESSES; TRANSIENTS; XENON; XENON 139

Citation Formats

Wahlgren, M A. NUCLEAR DECAY SCHEME STUDIES ON SHORT-LIVED NUCLIDES FROM THE (n,$gamma$) AND (n, FISSION) REACTIONS. United States: N. p., 1961. Web.
Wahlgren, M A. NUCLEAR DECAY SCHEME STUDIES ON SHORT-LIVED NUCLIDES FROM THE (n,$gamma$) AND (n, FISSION) REACTIONS. United States.
Wahlgren, M A. Wed . "NUCLEAR DECAY SCHEME STUDIES ON SHORT-LIVED NUCLIDES FROM THE (n,$gamma$) AND (n, FISSION) REACTIONS". United States.
@article{osti_4016698,
title = {NUCLEAR DECAY SCHEME STUDIES ON SHORT-LIVED NUCLIDES FROM THE (n,$gamma$) AND (n, FISSION) REACTIONS},
author = {Wahlgren, M A},
abstractNote = {A study was made of nuclear decay schemes, primarily of short-lived nuclides, utilizing the irradiation facilities of the Ford Nuclear Reactor at the University of Michigan. Multichannel pulse-height analysis was applied to the study of short-lived fission products and to a search for unreported isomeric transitions among the (n, gamma ) reaction products. Irradiation and handling techniques were developed and instrumental modifications made to facilitate the study of short-lived nuclides. The neutron flux and flux distribution at the irradiation position were measured. A simple and rapid separation of gaseous fission products into krypton and xenon fractions was developed. The primary gamma energies of 3.2-min Kr/sup 89/, 33 sec Kr/sup 90/, 1.2min Rb/sup 91m/, 41- sec Xe/sup 139/, and 66-sec Cs/sup 140/ we re determined and relative gamma intensities measured. Maximum beta energy end-points were measured for Kr/sup 89/ , Kr/sup 90/, Xe/sup 139/ s, Cs/sup 140/, and 9.5 min Cs/sup 139/, and lower limits established f or the decay energies of these nuclides. The gamma rays of the daughter activities, 14.9-min Rb/sup 89/, 2.7-min Rb/sup 90/, and Cs/sup 139/ , previously reported in the literature were verified. An upper limit of 2 minutes was established for the halflife of the fission product, Rh/sup 109/, by devising a chemical separation, requiring 6 min, giving decontamination factors of > 10/sup 5/ from other elements. An isomeric level of Pt/sup 199/ was detected and characterized by the (n, gamma ) reaction on normal and enriched platinum samples. The isomer decayed with a half-life of 14.1 plus or minus 0.3 sec by emission of gamma rays of 32 plus or minus 2 kev and 393 plus or minus 2 kev energy. The thermal neutron cross-section for the formation of the isomer was 28 plus or minus 3 mb. A long-lived isomer of Ag/sup 108/ was detected in Ag/sup 110//sup m/ tracer sources sufficiently old that the masking 270 day Ag/sup 110//sup m/ had decayed out. The half-life of the isomer was found to be > 5 years. 90% of the disintegrations proceeded by electron capture followed by a cascade of three gamma rays of 434-, 616-, and 722-kev energy, and 10% went by isomeric transition to 2.4-min Ag/sup 108/. New values were determined for the branching ratios in 2.4-min Ag/sup 108/. No unreported isomeric transitions, with half-lives in the range of 1 sec to 10 min, were detected in the (n, gamma ) reaction on ruthenium, palladium, mercury, rhenium, barium, lanthanum, cerium, praseodymium, samarium, europium, gadohinium, terbium, holmium, erbiu, thulium, ytterbium, or lutetium. (auth)},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1961},
month = {2}
}

Technical Report:
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