Decay of ${}^{149}{Er}^{g + m}$ by positron and delayed proton emission and by electron capture

In this study the decay of

{}^{149}{Er}^{g + m}

by positron emission, electron capture, and β-delayed proton emission was investigated. Gamma rays associated with

{}^{149}{Er}^{m}

decay were placed in a decay scheme on the basis of γγ and xγ coincidences and half-life. We assigned 120 γ rays deexciting 91 levels in

{}^{149}{Ho}

to 8.9±0.2 s

{}^{149}{Er}^{m}

decay. The π

s_{1 / 2}

single-particle state in

{}^{149}{Ho}

was observed to occur at 49.0 keV above the π

h_{11 / 2}

ground state. A (3.5±0.7) % isomeric transition decay branch and a (0.18±0.07) % β-delayed proton decay branch were determined for

{}^{149}{Er}^{m}

decay. Three additional γ rays were assigned to 4±2 s

{}^{149}{Er}^{g}

decay and a (7±2) % β-delayed proton decay branch was determined. Measured EC/

β^{+}

ratios to proton emitting states in

{}^{149}{Ho}

resulted in a (

Q_{EC}

S_{p}

)=7.

0_{- 0.4}^{+ 5.0}

MeV for

{}^{149}{ER}^{8}

decay and a

S_{p}

=1.

4_{- 0.6}^{+ 10}

MeV for Ho. The β-delayed proton spectrum from

{}^{149}{Er}^{g}

consisted of a highly structured component corresponding to the deexcitation of levels between 4 and 5 MeV in

{}^{149}{Ho}

and a structureless component corresponding to decay from higher levels. The β-strength function...

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Decay ofErg+m149by positron and delayed proton emission and by electron capture