W. Gins

High-precision mass measurements of the ground and isomeric states in $^{124,125}$Ag

J. Ruotsalainen [1], D. A. Nesterenko [1], M. Stryjczyk [1], A. Kankainen [1], L. Al Ayoubi [1,2], O. Beliuskina [1], L. Canete [1], P. Chauveau [3], R. P. de Groote [1], P. Delahaye [4], T. Eronen [1], M. Flayol [5], Z. Ge [6,1], S. Geldhof [1], W. Gins [1], M. Hukkanen [1,5], A. Jaries [1], D. Kahl, D. Kumar [6], I. D. Moore [1], S. Nikas [1], H. Penttilä, D. Pitman-Weymouth [8], A. Raggio [1], S. Rinta-Antila [1], A. de Roubin [1], M. Vilen [1], V. Virtanen, M. Winter [1]

Abstract

The masses of the ground and isomeric states in $^{124,125}$Ag have been measured using the phase-imaging ion-cyclotron-resonance technique at the JYFLTRAP double Penning trap mass spectrometer. The ground states of $^{124}$Ag and $^{125}$Ag were found to be 30(250) keV and 250(430) keV less bound but 36 and 110 times more precise than in the Atomic Mass Evaluation 2020, respectively. The excitation energy of $^{124}$Ag$^{m}$, ${E_x = 188.2(25)}$ keV, was determined for the first time. The new precise mass values have been utilised to study the evolution of nuclear structure via two-neutron separation energies. The impact on the astrophysical rapid neutron capture process has been investigated via neutron-capture reaction rate calculations. The precision measurements indicate a more linear trend in two-neutron separation energies and reduce the mass-related uncertainties for the neutron-capture rate of $^{124}$Ag$(n,γ)^{125}$Ag by a factor of around 100. The new mass values also improve the mass of $^{123}$Pd, previously measured using $^{124}$Ag as a reference.

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.

Precision mass measurements in the zirconium region pin down the mass surface across the neutron midshell at $N=66$

M. Hukkanen, W. Ryssens, P. Ascher, M. Bender, T. Eronen, S. Grévy, A. Kankainen, M. Stryjczyk, O. Beliuskina, Z. Ge, S. Geldhof, M. Gerbaux, W. Gins, A. Husson, D. A. Nesterenko, A. Raggio, M. Reponen [1], S. Rinta-Antila [1], J. Romero [1], A. de Roubin [1], V. Virtanen [1], A. Zadvornaya [1]

Abstract

Precision mass measurements of $^{104}$Y, $^{106}$Zr, $^{104,104m,109}$Nb, and $^{111,112}$Mo have been performed with the JYFLTRAP double Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line facility. The order of the long-lived states in $^{104}$Nb was unambiguously established. The trend in two-neutron separation energies around the $N=66$ neutron midshell appeared to be steeper with respect to the Atomic Mass Evaluation 2020 extrapolations for the $_{39}$Y and $_{40}$Zr isotopic chains and less steep for the $_{41}$Nb chain, indicating a possible gap opening around $Z=40$. The experimental results were compared to the BSkG2 model calculations performed with and without vibrational and rotational corrections. All of them predict two low-lying minima for $^{106}$Zr. While the unaltered BSkG2 model fails to predict the trend in two-neutron separation energies, selecting the more deformed minima in calculations and removing the vibrational correction, the calculations are more in line with experimental data. The same is also true for the $2^+_1$ excitation energies and differences in charge radii in the Zr isotopes. The results stress the importance of improved treatment of collective corrections in large-scale models and further development of beyond-mean-field techniques.

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 $N=70$.

Odd-odd neutron-rich rhodium isotopes studied with the double Penning trap JYFLTRAP

M. Hukkanen [1,2], W. Ryssens [3], P. Ascher [2], M. Bender, T. Eronen [1,2], S. Grévy, A. Kankainen [1], M. Stryjczyk [1], L. Al Ayoubi [1,5], S. Ayet [6], O. Beliuskina [1], C. Delafosse [1], W. Gins [1], M. Gerbaux [2], A. Husson [2], A. Jokinen [1], D. A. Nesterenko, I. Pohjalainen [1], M. Reponen [1], S. Rinta-Antila [1], A. de Roubin [1,7], A. P. Weaver

Abstract

Precision mass measurements of neutron-rich rhodium isotopes have been performed at the JYFLTRAP Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line (IGISOL) facility. We report results on ground- and isomeric-state masses in $^{110,112,114,116,118}$Rh and the very first mass measurement of $^{120}$Rh. The isomeric states were separated and measured for the first time using the phase-imaging ion-cyclotron-resonance (PI-ICR) technique. For $^{112}$Rh, we also report new half-lives for both the ground state and the isomer. The results are compared to theoretical predictions using the BSkG1 mass model and discussed in terms of triaxial deformation.

The MORA project

P. Delahaye [1,2], E. Liénard, I. Moore [3], M. Benali [2], M. L. Bissell [4], L. Canete [3], T. Eronen [3], A. Falkowski [5,2], X. Fléchard, M. Gonzalez-Alonso [6], W. Gins [7], R. P. De Groote [3], A. Jokinen [3], A. Kankainen [3], M. Kowalska [6], N. Lecesne [1], R. Leroy [1], Y. Merrer [2], G. Neyens [6,7], F. De Oliveira Santos [1], G. Quemener [2], A. De Roubin [3], B. -M. Retailleau [1], T. Roger [1], N. Severijns [7], J. C. Thomas [1], K. Turzo [1], P. Ujic [1]

Abstract

The MORA (Matter's Origin from the RadioActivity of trapped and oriented ions) project aims at measuring with unprecedented precision the D correlation in the nuclear beta decay of trapped and oriented ions. The D correlation offers the possibility to search for new CP-violating interactions, complementary to searches done at the LHC and with Electric Dipole Moments. Technically, MORA uses an innovative in-trap orientation method which combines the high trapping efficiency of a transparent Paul trap with laser orientation techniques. The trapping, detection, and laser setups are under development, for first tests at the Accelerator laboratory, JYFL, in the coming years.