Isochronous mass spectrometry at the RIKEN Rare-RI Ring facility

TL;DR

The paper presents the Rare-RI Ring, a dedicated isochronous storage ring at RIKEN for high-precision mass measurements of short-lived, neutron-rich nuclei, demonstrating its capability to achieve high accuracy within milliseconds.

Contribution

Introduction of the Rare-RI Ring facility employing isochronous mass spectrometry for precise, rapid mass measurements of exotic nuclei, with demonstrated high accuracy in initial tests.

Findings

Mass measurement precision of 10^{-5} achieved

Successful demonstration with neutron-rich nuclei

Rapid measurement within less than 1 ms

Abstract

A dedicated isochronous storage ring, named the Rare-RI Ring, was constructed at the RI Beam Factory of RIKEN, aiming at precision mass measurements of nuclei located in uncharted territories of the nuclear chart. The Rare-RI Ring employs the isochronous mass spectrometry technique with the goal to achieve a relative mass precision of $10^{-6}$ within a measurement time of less than 1 ms. The performance of the facility was demonstrated through mass measurements of neutron-rich nuclei with well-known masses. Velocity or magnetic rigidity is measured for every particle prior to its injection into the ring, wherein its revolution time is accurately determined. The latter quantity is used to determine the mass of the particle, while the former one is needed for non-isochronicity corrections. Mass precisions on the order of $10^{-5}$ were achieved in the first commissioning, which demonstrates that Rare-RI Ring is a powerful tool for mass spectrometry of short-lived nuclei.