Nuclear structure effects in the mass region aroundA=100, derived from experimentalQ ? -values

Abstract

The endpoint energies of r in 15 neuron-rich nuclei with mass numbers 101 <AN 106 have been measured with a plastic scintillator telescope in coincidence with a large Ge(Li)-detector at the on-line mass separator LOHENGRIN. From the Qp-values obtained in these experiments, nuclear structure effects in this region of the nuclear chart are deduced. Finally, nuclear masses derived from these Qp-values are compared with the predictions of different theoretical mass calculations.

Discovery of yttrium, zirconium, niobium, technetium, and ruthenium isotopes

“…"In addition, evidence was obtained that the 60d Nb has a mass assignment of 91, clarifying certain previous transmutations studies, and that the 18h Nb positron emitter is Nb 90 ." These half-lives are close to the currently adopted values of 14.60(5) h and 60.86 (22) d for 90 Nb and 91 Nb, respectively. The half-life for 91 Nb corresponds to an isomeric state.…”

The deformedN=60 nucleus 41 101 Nb

“…Ar and Ar are the peak areas of the X rays and the V rays, respectively, and eK and e~ the detection efficiencies for them. The conversion coefficient is c~K(119.3 keV) 916(53)57 (24) x ~210"0 x 1.60 x 0@90=0.15 (7). The procedure has been checked using transitions with known multipolarity of neighbouring nuclei which were present in the beam of JOSEF.…”

Measurements of?-endpoint-energies using a magnetic electron separator

“…The Braunschweig group [17] has also performed systematic fi-?,-coincidence measurements using a plastic detector telescope. This detector has a higher efficiency than the Ge(HP)-detector, however larger error bars as shown in the fifth column of Table 1.…”