hide
Free keywords:
-
MPINP:
Präzisionsexperimente - Abteilung Blaum
Abstract:
Masses of 112Sn projectile fragments were measured employing isochronous mass spectrometry at the Cooler Storage Ring in Lanzhou. Different from the previous data analysis method, relying on the arithmetic mean revolution times of the stored fragments, we introduce an exponentially modified Gaussian function to describe the asymmetric peak shapes. This new approach enables us to properly deconvolute the overlapping peaks of stored ions and to accurately determine their masses. The mass excesses of 103Sn and the low-lying 1/2− isomers in 87Mo, 91Ru, and 95Pd were directly measured for the first time, and the masses of 69As, 73Br, 75Kr, 79Sr, and 81Y were redetermined with higher precision comparable to that of Penning-trap mass spectrometry. Based on the new mass value of 103Sn, the previously unknown masses of 104Sb, 107Te, 108I, 111Xe, and 112Cs were obtained indirectly by using the literature proton and/or α decay energies. Systematic trends of the excitation energies of the Jπ=1/2− isomers in the N=47,49 isotones are well reproduced by the state-of-the-art shell model calculations with the tensor forces included.
