S. Kujanpää

Isomeric states of fission fragments explored via Penning trap mass spectrometry at IGISOL

A. Jaries [1], M. Stryjczyk [1], A. Kankainen [1], L. Al Ayoubi [1,2], O. Beliuskina [1], L. Canete [1], R. P. de Groote, C. Delafosse [1], P. Delahaye [3], T. Eronen [1], M. Flayol [4], Z. Ge [5,1], S. Geldhof [1], W. Gins [1], M. Hukkanen [1,4], P. Imgram [6], D. Kahl, J. Kostensalo [8,1], S. Kujanpää, D. Kumar [5,1], I. D. Moore, M. Mougeot [1], D. A. Nesterenko, S. Nikas [1], D. Patel [9,1], H. Penttilä, D. Pitman-Weymouth [10], I. Pohjalainen [1], A. Raggio [1], M. Ramalho [1], M. Reponen [1], S. Rinta-Antila [1], A. de Roubin [1,4], J. Ruotsalainen [1,9], P. C. Srivastava, J. Suhonen [1,11], M. Vilen [1], V. Virtanen [1], A. Zadvornaya [1]

Abstract

The masses of $^{84}$Br, $^{105}$Mo, $^{115,119,121}$Pd, $^{122}$Ag, $^{127,129}$In, $^{132}$Sb and their respective isomeric states have been measured with the JYFLTRAP Penning trap mass spectrometer using the phase-imaging ion-cyclotron-resonance technique. The excitation energies of the isomeric states in $^{132}$Sb and $^{119}$Pd were experimentally determined for the first time, while for $^{84}$Br, $^{115}$Pd and $^{127,129}$In, the precision of the mass values was substantially improved. In $^{105}$Mo and $^{121}$Pd there were no signs of a long-lived isomeric state. The ground-state measurements of $^{119}$Pd and $^{122}$Ag indicated that both are significantly more bound than the literature values. For $^{122}$Ag, there was no indication of a proposed third long-lived state. The results for the $N=49$ nucleus $^{84}$Br and isomers close to doubly magic $^{132}$Sn have been compared to the shell-model and the microscopic quasiparticle-phonon model calculations.

High-precision Penning-trap mass measurements of Cd and In isotopes at JYFLTRAP remove the fluctuations in the two-neutron separation energies

A. Jaries [1], M. Stryjczyk [1], A. Kankainen [1], L. Al Ayoubi [1,2], O. Beliuskina [1], P. Delahaye [3], T. Eronen [1], M. Flayol [4], Z. Ge [5,1], W. Gins [1], M. Hukkanen [1,4], D. Kahl [1], S. Kujanpää, D. Kumar [5,1], I. D. Moore, M. Mougeot [1], D. A. Nesterenko, S. Nikas [1], H. Penttilä, D. Pitman-Weymouth [7], I. Pohjalainen [1], A. Raggio [1], W. Rattanasakuldilok [1], A. de Roubin [4], J. Ruotsalainen [1], V. Virtanen [1]

Abstract

We report on the first direct mass measurements of the $^{118,119}$Cd and $^{117-119}$In isotopes performed at the Ion Guide Isotope Separator On-Line facility using the JYFLTRAP double Penning trap mass spectrometer. The masses of $^{117}$In and $^{118}$Cd isotopes are in agreement with the literature, while $^{118,119}$In and $^{119}$Cd differ from literature by 49, 13 and 85 keV (6.1, 1.9 and 2.1 standard deviations), respectively. The excitation energy of the $^{118}$In first isomeric state, $E_x = 40.3(25)$ keV, was determined for the first time. The updated mass values removed the fluctuations observed in the two-neutron separation energies and lead to a smoother linear decrease of both isotopic chains. The $\log(ft)$ value for the $^{118}$Cd decay is also found to increase from 3.93(6) to 4.089(8). The reported results indicate an absence of significant structural changes around $N=70$.