Investigation of neutron deficient Zr and Nb nuclei with heavy ion induced compound reactions

Abstract

32S and 12C induced compound reactions on Fe, Ni and Se targets have been used to produce neutron deficient nuclei in the mass region 84 _< A < 87. In-beam ?-ray spectroscopy consisting of the measurement of excitation functions, 77 coincidences and ?-ray angular distributions has been performed. The following level energies and spin-parity values have been deduced:

Heavy-ion in-beam studies of the nucleus87Nb

“…The 9/2 + band head lies at 3.9 keV excitation and appears to be the r-active isomeric state which was proposed in previous experiments [11,12]. The 9/2 + band head lies at 3.9 keV excitation and appears to be the r-active isomeric state which was proposed in previous experiments [11,12].…”

“…In the A = 87 decay chain most transitions can be attributed to the B-decays of two states in 87Nb with known halflives of T~/2 = 2.6 rain and 3.8 rain [11,12]. The activity spectra which had been started a few seconds after a long irradiation contain y-rays from the A = 84, 86 and 87 decay chains.…”

“…Apart from preliminary work on the A = 87 B-decay chain [11,12] and transitions which Korschinek et al [12] and Cordova [13] attributed to the 58Ni(32S, 3p)87Nb reaction, no in-beam information on STNb was known to us. Abundant results have also been gathered by us on other essentially unknown nuclides, i.e.…”

The 8+ levels of86Zr revisited

“…Three reports of the yrast level structure of the N =46 nucleus 86Zr can be found in the literature [1][2][3]. Unfortunately, the three do not agree above the J~=6 + sta~e; this disagreement is reflected in the Nuclear Data Sheets compilation for A= 86 [4].…”

“…Unfortunately, the three do not agree above the J~=6 + sta~e; this disagreement is reflected in the Nuclear Data Sheets compilation for A= 86 [4]. The structure of 86Zr is quite interesting from the point of view of understanding the shape transition which appears to occur in Kr, Sr and Zr isotopes as neutrons are removed from the N = 50 shell [1,[5][6][7][8]. While the N=50 and N=48 nuclei appear to be quite well described by the spherical shell model, the N=42 nuclei appear to be well deformed.…”