Decay of /sup 149/Er/sup g//sup +//sup m/ by positron and delayed proton emission and by electron capture

Journal Article · Sat Dec 31 23:00:00 EST 1988 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.39.219· OSTI ID:6535540

Firestone, R B; Nitschke, J M; Wilmarth, P A; Vierinen, K; Gilat, J; Toth, K S; Akovali, Y A

In this study the decay of /sup 149/Er/sup g//sup +//sup m/ by positron emission, electron capture, and ..beta..-delayed proton emission was investigated. Gamma rays associated with /sup 149/Er/sup m/ decay were placed in a decay scheme on the basis of ..gamma gamma.. and x..gamma.. coincidences and half-life. We assigned 120 ..gamma.. rays deexciting 91 levels in /sup 149/Ho to 8.9 +- 0.2 s /sup 149/Er/sup m/ decay. The ..pi..s/sub 1/2/ single-particle state in /sup 149/Ho was observed to occur at 49.0 keV above the ..pi..h/sub 11/2/ ground state. A (3.5 +- 0.7) % isomeric transition decay branch and a (0.18 +- 0.07) % ..beta..-delayed proton decay branch were determined for /sup 149/Er/sup m/ decay. Three additional ..gamma.. rays were assigned to 4 +- 2 s /sup 149/Er/sup g/ decay and a (7 +- 2) % ..beta..-delayed proton decay branch was determined. Measured EC/..beta../sup +/ ratios to proton emitting states in /sup 149/Ho resulted in a (Q/sub E//sub C/-S/sub p/) = 7.0/sup +5.0//sub -0.4/ MeV for /sup 149/ER/sup 8/ decay and a S/sub p/ = 1.4/sup +10//sub -0.6/ MeV for Ho. The ..beta..-delayed proton spectrum from /sup 149/Er/sup g/ consisted of a highly structured component corresponding to the deexcitation of levels between 4 and 5 MeV in /sup 149/Ho and a structureless component corresponding to decay from higher levels. The ..beta..-strength function for /sup 149/Er/sup g//sup +//sup m/ decay is discussed in terms of single-particle shell-model structure, weak coupling to the /sup 148/Dy core, and decay of ..pi..h/sub 11/2/ protons across the shell closure to the ..nu..h/sub 9/2/ neutron orbital.

• Research Organization: Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
• OSTI ID: 6535540
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 39:1; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

651720* -- Nuclear Properties & Reactions
A=90-149
Experimental
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCELERATORS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BARYONS
BETA DECAY
BETA-PLUS DECAY
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
COMPOUND-NUCLEUS REACTIONS
DATA
DECAY
DELAYED PROTONS
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE DECAY
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
ERBIUM 149
ERBIUM ISOTOPES
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FERMIONS
GAMMA RADIATION
HADRONS
HALF-LIFE
HEAVY ION ACCELERATORS
HEAVY ION REACTIONS
HILACS
HOLMIUM 149
HOLMIUM ISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
IONIZING RADIATIONS
ISOTOPES
LEPTONS
LINEAR ACCELERATORS
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 100-1000
MOLYBDENUM 94 TARGET
NICKEL 58 REACTIONS
NUCLEAR DECAY
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUMERICAL DATA
ODD-EVEN NUCLEI
PARTICLE MODELS
POSITRONS
PROTON EMISSION DECAY
PROTON SPECTRA
PROTONS
RADIATIONS
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SHELL MODELS
SINGLE-PARTICLE MODEL
SPECTRA
SUPERHILAC
TARGETS