Isochronous mass measurement of short-lived nuclei at the CSRe in Lanzhou

Masses are basic nuclear properties. Their accurate knowledge is particularly important for nuclear structure and nuclear astrophysics. The challenge today is to obtain accurate masses of nuclei located far away from the valley of 𝛽-stability. However, such nuclei are as a rule short-lived and are produced with tiny yields. Therefore, highly efficient and fast measurement techniques are required. The Isochronous Mass Spectrometry (IMS) is one of such techniques which is realized at in-flight radioactive ion beam facilities. The IMS experiments are performed today at three heavy-ion storage ring facilities, namely at the experimental storage ring ESR at GSI Helmholtz Center in Darmstadt, at the experimental cooler-storage ring CSRe at the Institute of Modern Physics in Lanzhou, and at the rare-ion storage ring R3 at the RIKEN Nishina Center in Tokyo. Since the first IMS experiment was performed at CSRe storage ring in 2008, many neutron-deficient and neutron-rich nuclei have been measured using the IMS. Besides, the existing IMS has been updated with additional velocity measurement since 2013. The mass resolving power of IMS have been much improved with additional velocity measurement. In this talk, we will give an introduction to the IMPCAS accelerator facility and the isochronous mass spectrometry applied at the CSRe. A special emphasis will be given to the recent improvements of the IMS technology. We will also present some very recent mass measurement results.

R.J.Chen^a,c, Y.M. Xing^a, M.Wang^a,e, Y.H. Zhang^a,e, Yu. A.Litvinov^a,c, P. Shuai^a, X. Xu^a, X.L.Yan^a, X. Zhou^a, C.Y. Fu^a,b, W.W. Ge^a,b, H.F. Li^a, J.H. Liu^a, S. Litvinov^a,c, L.J. Mao^a, M.Si^a, M.Z. Sun^a, B. Wu^a, H.S. Xu^a,e, J.C. Yang^a, D.Y.  Yin^a, Y.J.Yuan^a, Q. Zeng^a,d, P. Zhang^a,b, M.Zhanga and X.H. Zhou^a,e

^aCAS Key Laboratory of High Precision Nuclear Spectroscopy and Center for Nuclear Matter Science, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China

^bUniversity of Chinese Academy of Sciences, Beijing, 100049, People’s Republic of China

^cGSI Helmholtzzentrum für Schwerionenforschung, Planckstraße 1, 64291 Darmstadt, Germany

^dResearch Center for Hadron Physics, National Laboratory of Heavy Ion Accelerator Facility in Lanzhou and University of Science and Technology of China, Hefei 230026, China

^eJoint Research Center for Modern Physics and Clean Energy, South China Normal University, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China