Yields of short-lived fission products produced following {sup 235}U(n{sub th},f)
- University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States)
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Measurements of gamma-ray spectra, following the thermal neutron fission of {sup 235}U have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10thinsp000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few seconds. Independent yields of many of these isotopes have rather large uncertainties, some of which have been reduced by the present study. {copyright} {ital 1998} {ital The American Physical Society}
- OSTI ID:
- 639188
- Journal Information:
- Physical Review, C, Vol. 58, Issue 2; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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