Mass measurement of Re-190

M R Griffiths,R Hertenberger,M Freer,H-F Wirth,R Gernhäuser,S Pirrie,Tz Kokalova,C Wheldon,V Ziman,Th Faestermann,R Krücken,J D Malcolm,M Barr,N I Ashwood,A Turner

doi:10.1088/1361-6471/ab98e3

Abstract

In this paper, a measurement of the atomic mass and mass excess of are presented. This isotope and were produced at the Maier-Leibnitz Laboratory (MLL) in Munich in the 192Os(d, α)190Re and 194Pt(d, α)192Ir reactions. The Q3D magnetic spectrograph was used to measure the momenta of the α-particle ejectiles in order to reconstruct states in both 190Re and 192Ir. A mass calibration was performed using known energy levels in 192Ir. These measurements were used to obtain a new value of the mass excess of 190Re, −35583 ± 5 keV. The previously known literature value is −35640 ± 70 keV.

Highlights

The neutron-rich isotope 17950Re115 lies on the decay path of nuclei populated in the astrophysical rapid neutron capture process
In this paper, a measurement of the atomic mass and mass excess of 19705Re are presented. This isotope and 17972Ir were produced at the Maier-Leibnitz Laboratory (MLL) in Munich in the 192Os(d, α)190Re and 194Pt(d, α)192Ir reactions
The peak widths of about 10 keV full width at half maximum (FWHM) are dominated by experimental resolution, the most significant contribution to which are the energy-loss differences of α-particle ejecticles due to the target thickness

Summary

Introduction

The neutron-rich isotope 17950Re115 lies on the decay path of nuclei populated in the astrophysical rapid neutron capture process (the r-process). The mass ≈170–190 region of the nuclide chart is known for the occurrence of large numbers of metastable (isomeric) nuclear states caused by significant quadrupole deformations [1]. Schatz [6] has pointed out the importance of determining masses to better than 10 keV for understanding astrophysical processes, as it means uncertainties in the mass do not dominate over reaction-rate uncertainties (reference [6] is focused on the rp-process, but this condition has been shown to apply to other astrophysical processes, such as the r-process [7]) This allows production mechanisms to be more investigated. This paper details an experiment that has been performed to accurately measure the mass of 190Re

Experimental method

Results

Uncertainty