Search for alpha decay of 151Eu to the first excited level of 147Pm using underground gamma-ray spectrometry

The alpha decay of 151Eu to the first excited level of 147Pm (Jpi = 5/2+, Eexc = 91.1keV) was searched for at the HADES underground laboratory (≈ 500m w.e.). A sample of high-purity europium oxide with mass of 303 g and a natural isotopic composition has been measured over 2232.8 h with a high energy resolution ultra-low background n-type semi-planar HPGe detector (40 cm3) with sub-micron deadlayer. The new improved half-life limit has been set as T1/2 ≥ 3.7×1018 y at 68% CL. Possibilities to improve the sensitivity of the experiment, which is already near the theoretical predictions, are discussed. New half-life limit for alpha decay of 153Eu is also determined as T1/2 ≥ 5.5 × 1017 y.

DANEVICH F.A.;  ANDREOTTI Erica;  HULT Mikael;  MARISSENS Gerd;  TRETYAK V.I.;  YÜKSEL Ayhan; 

2012-12-14

SPRINGER

JRC72349

1434-6001,   

http://dx.doi.org/10.1140/epja/i2012-12157-7,    https://publications.jrc.ec.europa.eu/repository/handle/JRC72349,   

10.1140/epja/i2012-12157-7,