<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>B</mml:mi><mml:mi>ρ</mml:mi></mml:mrow></mml:math>-defined isochronous mass spectrometry: An approach for high-precision mass measurements of short-lived nuclei
M. Wang, M. Zhang, X. H. Zhou, Y. H. Zhang, Yu. A. Litvinov, X. Xu, Rui Jiu Chen, Huiyong Deng, Chuancheng Fu, Wenwei Ge, H. F. Li, Ting Liao, S. Litvinov, P. Shuai, Jian Shi, M. Si, R. S. Sidhu, Y. N. Song, M. Z. Sun, Shinji Suzuki, Q. Wang, Y. M. Xing, X. Xu, Takayuki Yamaguchi, X. L. Yan, Jiancheng Yang, Youjin Yuan, Q. Zeng, X. H. Zhou
Abstract
A technique for broadband high-precision mass measurements of short-lived exotic nuclides is reported. It is based on the isochronous mass spectrometry (IMS) and realizes simultaneous determinations of revolution time and velocity of short-lived stored ions at the cooler storage ring CSRe in Lanzhou. The technique, named the $B\ensuremath{\rho}$-defined IMS or $B\ensuremath{\rho}$-IMS, boosts the efficiency, sensitivity, and accuracy of mass measurements, and is applied here to measure masses of neutron-deficient $fp$-shell nuclides. In a single accelerator setting, masses of $^{46}\mathrm{Cr}$, $^{50}\mathrm{Fe}$, and $^{54}\mathrm{Ni}$ are determined with relative uncertainties of (5--6)$\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$, thereby improving the input data for testing the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. This is the technique of choice for future high-precision measurements of the most rarely produced shortest-lived nuclides.