Delayed proton emission of N = 81 odd-odd precursors: /sup 148/Ho, /sup 150/Tm , and /sup 152/Lu
Beta-delayed proton decay was observed in /sup 148/Ho, /sup 150/Tm, and /sup 152/Lu for the first time. Contrary to neighboring even-Z N = 81 isotones, the proton spectra appear structureless and statistical in nature. Proton branching ratios for the high-spin isomers in these isotopes, based on the intensity of ..gamma..-ray transitions in the intermediate nuclei, are (8..sqrt../sub 2//sup +1/) x 10/sup -4/, (1.2/sub -0.4//sup +0.2/) x 10/sup -2/, and (1.5 +- 0.7) x 10/sup -1/, respectively. The onset of proton emission in all three cases occurs at a proton to ..gamma.. width ratio of about 10/sup -4/. Protons were found to be in coincidence with x rays, ..gamma.. rays, and positrons. Coincident K x rays served to identify the Z of the precursor, while the ..gamma.. rays gave quantitative information about proton decay to excited states in the daughter nuclei. By comparing the final state branching ratios with statistical model calculations, it was concluded that /sup 148/Ho and /sup 150/Tm both have isomers with probable spin values of 1/sup +/ and 6/sup -/. Statistical model calculations with ''standard'' prescriptions for level densities and ..gamma.. widths, and with a reduced level density parameter are compared to experiment. To reproduce the shape of the proton spectrum it was necessary to assume Gaussian-shaped Gamow-Teller ..beta.. strength functions centered near 8 MeV excitation energy. In the course of these experiments ..beta..-delayed proton emission in /sup 148/Er was also identified.
- Research Organization:
- Lawrence Berkeley Laboratory, Berkeley, California 94720
- OSTI ID:
- 5122884
- Journal Information:
- Phys. Rev. C; (United States), Vol. 37:6
- Country of Publication:
- United States
- Language:
- English
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HOLMIUM 148
DECAY
LUTETIUM 152
THULIUM 150
BRANCHING RATIO
COINCIDENCE SPECTROMETRY
DELAYED PROTON PRECURSORS
ENERGY-LEVEL TRANSITIONS
GAMMA RADIATION
GAMOW-TELLER RULES
GAUSSIAN PROCESSES
HIGH SPIN STATES
PARITY
POSITRONS
PROTON SPECTRA
SPIN
STATISTICAL MODELS
X RADIATION
ANGULAR MOMENTUM
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
HOLMIUM ISOTOPES
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
LEPTONS
LUTETIUM ISOTOPES
MATHEMATICAL MODELS
NUCLEI
ODD-ODD NUCLEI
PARTICLE PROPERTIES
RADIATIONS
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SECONDS LIVING RADIOISOTOPES
SPECTRA
THULIUM ISOTOPES
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