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

Journal Article · Sun Jan 01 00:00:00 EST 1989 · 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), Vol. 39:1
• Country of Publication: United States
• Language: English

Related Subjects

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