First Online Mass Measurements of Isobar Chains via Multi-Reflection Time-of-Flight Mass Spectrograph Coupled with GARIS-II

TL;DR

This paper reports the first online mass measurements of isobar chains using a multi-reflection time-of-flight spectrograph coupled with GARIS-II, enabling precise determination of heavy nuclei masses produced in fusion-evaporation reactions.

Contribution

It introduces a novel setup combining MRTOF-MS with GARIS-II for direct, high-precision mass measurements of heavy nuclei in an online environment.

Findings

Measured masses of 205,206Fr, 201At, and 201Po with high precision.

Observed time-of-flight spectra for three isobar chains.

Demonstrated the capability of the system for online mass spectrometry of heavy nuclei.

Abstract

Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located after a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the masses of several heavy nuclei have been directly and precisely measured. The nuclei were produced via fusion-evaporation reactions and separated from projectile-like and target-like particles using GARIS-II before being stopped in a helium-filled gas cell. Time-of-flight spectra for three isobar chains, 205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were observed. Precision atomic mass values were determined for 205,206Fr, 201At, and 201Po.