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arXiv · 1811.12595

Experimental Investigation of the Transition Energy $γ_t$ in the Isochronous Mode of the HIRFL-CSRe

W. W. Ge·Y. J. Yuan·J. C. Yang·R. J. Chen·X. L. Yan·H. Du·Z. S. Li·J. Yang·D. Y. Yin·L. J. Mao·X. N. Li·W. H. Zheng·G. D. Shen·B. Wu·S. Ruan·G. Wang·H. Zhao·M. Wang·M. Z. Sun·Y. M. Xing·P. Zhang·C. Y. Fu·P. Shuai·X. Xu·Y. H. Zhang·T. Bao·X. C. Chen·W. J. Huang·H. F. Li·J. H. Liu·Yu. A. Litvinov·S. Litvinov·Q. Zeng·X. Zhou
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Abstract

The Isochronous Mass Spectrometry (IMS) based on storage rings is a powerful technique for mass measurement of short-lived exotic nuclei. The transition energy $γ_t$ of the storage ring is a vital parameter of the IMS technique. It is difficult to measure the $γ_t$ and its relation to momentum spread or circulating length, especially to monitor the variation of $γ_t$ during experiments. An experimental investigation on the $γ_t$ has been performed for the IMS experiment at the Cooler Storage Ring of the Heavy Ion Research Facility in Lanzhou (HIRFL-CSRe). With the velocity measured by two time-of-flight (TOF) detectors, the $γ_t$ as a function of orbital length can be determined. The influences of higher order magnetic field components on the $γ_t$ function were inferred for isochronous correction. This paper introduces and investigates the influence of dipole magnetic fields, quadrupole magnetic fields and sextupole magnetic fields on the $γ_t$ function. With the quadrupole magnets and sextupole magnets corrections, a mass resolution of 171332 (FWHM) and $σ(T)/T=1.34\times10^{-6}$ were reached, which shall be compared with 31319 (FWHM) and $σ(T)/T=7.35\times10^{-6}$ obtained without correction.

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W. W. Ge, Y. J. Yuan, J. C. Yang, R. J. Chen, X. L. Yan, H. Du, Z. S. Li, J. Yang, D. Y. Yin, L. J. Mao, X. N. Li, W. H. Zheng, G. D. Shen, B. Wu, S. Ruan, G. Wang, H. Zhao, M. Wang, M. Z. Sun, Y. M. Xing, P. Zhang, C. Y. Fu, P. Shuai, X. Xu, Y. H. Zhang, T. Bao, X. C. Chen, W. J. Huang, H. F. Li, J. H. Liu, Yu. A. Litvinov, S. Litvinov, Q. Zeng, X. Zhou. 2018-11-30. Experimental Investigation of the Transition Energy $γ_t$ in the Isochronous Mode of the HIRFL-CSRe. https://doi.org/10.1016/j.nima.2018.08.059

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