Development of Unstable Nuclear Beam 17N to Search for High-Spin Isomers in N=51 Isotones

In order to search for high-spin isomers in N=51 isotones, an unstable nuclear beam ¹⁷N was developed using the low-energy radioisotope beam separator(CRIB) of the Center for Nuclear Study(CNS), University of Tokyo, in RIKEN.

High-spin isomers in N=83 isotones have been systematically studied. These isomers are of stretch coupled configurations and oblate shape. High-spin isomers of N=51 isotones are expected to be stemmed from the same isomerism appeared in N=83 isotones.

Since the nuclei with Z <40 of N=51 isotones are close to the stability line, it is difficult to produce high-spin states in these nuclei using reactions by combinations of stable beams and targets. Therefore, it is very effective to use the radioisotope beam. Experiment was carried out by means of the γ spectroscopy method, Seven γ-rays emitted from Nb nuclei which were produced by the secondary fusion reaction of ⁸²Se + ¹⁷N were observed.