https://doi.org/10.1140/epja/s10050-023-00928-6
Regular Article – Experimental Physics
-defined isochronous mass spectrometry and mass measurements of 
Ni fragments
1
CAS Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China
2
School of Nuclear Science and Technology, University of Chinese Academy of Sciences, 100049, Beijing, China
3
GSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291, Darmstadt, Germany
4
Department of Physics, Saitama University, 338-8570, Saitama, Japan
5
School of Nuclear Science and Engineering, East China University of Technology, 330013, Nanchang, China
c
wangm@impcas.ac.cn
d
yhzhang@impcas.ac.cn
e
y.litvinov@gsi.de
Received:
31
October
2022
Accepted:
20
January
2023
Published online:
14
February
2023
A novel isochronous mass spectrometry, termed as -defined IMS, has been established at the experimental cooler-storage ring CSRe in Lanzhou. Its potential has been studied through high precision mass measurements of Ni projectile fragments. Two time-of-flight detectors were installed in one of the straight sections of CSRe, thus enabling simultaneous measurements of the velocity and the revolution time of each stored short-lived ion. This allows for calculating the magnetic rigidity and the orbit length C of each ion. The accurate 
function has been constructed, which is a universal calibration curve used to deduce the masses of the stored nuclides. The sensitivity to single stored ions, fast measurement time, and background-free characteristics of the method are ideally suited to address nuclides with very short lifetimes and smallest production yields. In the limiting case of just a single particle, the achieved mass resolving power allows one to determine its mass-over-charge ratio m/q with a remarkable precision of merely 
keV. Masses of 
fp-shell nuclides are re-determined with high accuracy, and the validity of the isospin multiplet mass equation is tested up to the heaviest isospin quartet with 
. The new masses are also used to investigate the mirror symmetry of empirical residual proton-neutron interactions.
© The Author(s) 2023
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
