Lu176: An unreliables-process chronometer
| Autor: | B. Sur, K. T. Lesko, C. Beausang, R.-M. Larimer, Eric B. Norman |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | Physical Review C. 44:2850-2864 |
| ISSN: | 1089-490X 0556-2813 |
| DOI: | 10.1103/physrevc.44.2850 |
| Popis: | A level scheme of {sup 176}Lu up to {approximately}1400 keV excitation energy is deduced from a gamma-gamma coincidence experiment and previously published particle transfer data. 170 gamma-ray transitions are placed between 85 levels, confirming many of the previously established levels and some of the decay scheme. A level at 835.5 keV (J{sup {pi}} = 5{sup {minus}}, t{sub 1/2} < 10 ns) decays with substantial strength to both the ground state (7{sup {minus}}, 4.08 {times} 10{sup 10} yr) and the 122.9 keV isomer (1{sup {minus}}, 3.7 hr). The presence of this level guarantees the thermal equilibration of {sup 176}Lu{sup g,m} for temperatures greater than 3 {times} 10{sup 8} K and therefore during s-process nucleosynthesis. The resulting extreme temperature sensitivity of its effective half-life rules out the use of {sup 176}Lu as an s-process chronometer. The use of {sup 176}Lu to determine s-process temperatures is discussed. 30 refs., 11 figs., 3 tabs. |
| Databáze: | OpenAIRE |
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