Decay of samarium isotopes: 140Sm, 141 mSm, 142Sm and 143( m+ g) Sm

Abstract

The isotopes of 140Sm, 141 m Sm, 142Sm and 143( m+ g) Sm were produced by the 144Sm(γ, xn) reactions. The cross bombardment technique was used for studying only the 143( m+ g) Sm isotopes. The decays of the isotopes through positron emission and γ-ray transition were followed with the Ge(Li) and plastic detectors. For the 143( m+ g) Sm isotopes, end point energy was determined and coincidence measurements were performed by gating on 511-, 1057- and 1516-keV γ-rays. Photon energies associated with the half-lives of 14·82, 22·8, 72·5, 1·08 and 8·85 min were assigned to the isotopes 140Sm, 141 m Sm, 142Sm and 143( m+ g) Sm, respectively. A decay scheme was proposed for the decay of 143( m+ g) Sm. The cross-sections of the 144Sm( n, 2 n) 143Sm and 143 g Sm reactions were determined as 429·5 and 661·2 m respectively.