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Lifetimes of gamma-ray transitions by delayed-coincidence measurements MacKenzie, Innes Keith
Abstract
An apparatus for the measurement of the lifetimes of gamma-ray transitions between nuclear excited states has been designed and constructed. With this apparatus, lifetimes as short as 1.5 x 10⁻¹⁰ seconds may be determined. This lower limit is shown to be inherent in the scintillation detectors available and not in the electronic circuits which are themselves capable of much better performance. Measurements have been carried out on several radioactive nuclei and have yielded the following results: (1) The two excited states of Ni⁶⁰ have half-lives less than 1.6 x 10⁻¹⁰ seconds. (2) The three excited states of Co⁵⁹ have half-lives less than 2 x 10⁻¹⁰ seconds. (3) No detectable half-life is found in the decay of Eu¹⁵²,¹⁵⁴. (4) An excited state with a half-life of 1.1 x 10⁻⁹ seconds is present in W¹⁸². We identify this transition as magnetic quadrupole. (5) A half-life.of 2.3 x 10⁻¹⁰ seconds is found for the .607 Mev transition in Te¹²⁴ which has previously been classified as electric quadrupole.
Item Metadata
Title |
Lifetimes of gamma-ray transitions by delayed-coincidence measurements
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1953
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Description |
An apparatus for the measurement of the lifetimes of gamma-ray transitions between nuclear excited states has been designed and constructed. With this apparatus, lifetimes as short as 1.5 x 10⁻¹⁰ seconds may be determined. This lower limit is shown to be inherent in the scintillation detectors available and not in the electronic circuits which are themselves capable of much better performance. Measurements have been carried out on several radioactive nuclei and have yielded the following results:
(1) The two excited states of Ni⁶⁰ have half-lives less than 1.6 x 10⁻¹⁰ seconds.
(2) The three excited states of Co⁵⁹ have half-lives less than 2 x 10⁻¹⁰ seconds.
(3) No detectable half-life is found in the decay of Eu¹⁵²,¹⁵⁴.
(4) An excited state with a half-life of 1.1 x 10⁻⁹ seconds is present in W¹⁸². We identify this transition as magnetic quadrupole.
(5) A half-life.of 2.3 x 10⁻¹⁰ seconds is found for the .607 Mev transition in Te¹²⁴ which has previously been classified as electric quadrupole.
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Genre | |
Type | |
Language |
eng
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Date Available |
2012-02-18
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0302619
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.