1. Alpha-decay-correlated mass measurement of 206,207Ra using an $\alpha$-TOF detector equipped MRTOF-MS system
- Author
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Niwase, T., Wada, M., Schury, P, Brionnet, P., Chen, S. D., Hashimoto, T., Haba, H., Hirayama, Y., Hou, D. S., Iimura, S., Ishiyama, H., Ishizawa, S., Ito, Y., Kaji, D., Kimura, S., Liu, J., Miyatake, H., Moon, J. Y., Morimoto, K., Morita, K., Nagae, D., Rosenbusch, M., Takamine, A., Tanaka, T., Watanabe, Y. X., Wollnik, H., Xian, W., and Ya, S. X.
- Subjects
Nuclear Experiment - Abstract
The atomic masses of the isotopes $^{206,207}$Ra have been measured via decay-correlated mass spectroscopy using a multi-reflection time-of-flight mass spectrograph equipped with an $\alpha$-TOF detector. The Ra isotopes were produced as fusion-evaporation products in the $^{51}$V+$^{159}$Tb reaction system and delivered by the gas-filled recoil ion separator GARIS-II at RIKEN. The $\alpha$-TOF detector provides for high-accuracy mass measurements by correlating time-of-flight signals with subsequent $\alpha$-decay events. The masses of $^{206}$Ra and $^{207g,m}$Ra were directly measured using a multi-reflection time-of-flight mass spectrograph equipped with an $\alpha$-TOF detector. A mass excess of ME = 3538(15) keV/c$^2$ and an excitation energy of E$_{\rm ex}$ = 552(42) keV were determined. The $\alpha$-decay branching ratio of $^{207m}$Ra, b$\alpha$ = 0.26(20), was directly determined from decay-correlated time-of-flight signals, and the reduced alpha width of $^{207m}$Ra was calculated to be $\delta^2$ = 50+62-41 keV from the branching ratio. The spin-parity of $^{207m}$Ra was confirmed to be $J^\pi$ = 13/2$^-$ from decay correlated mass measurement results.
- Published
- 2021