English

Alpha-decay-correlated mass measurement of 206,207Ra using an $\alpha$-TOF detector equipped MRTOF-MS system

Nuclear Experiment 2021-10-20 v2

Abstract

The atomic masses of the isotopes 206,207^{206,207}Ra have been measured via decay-correlated mass spectroscopy using a multi-reflection time-of-flight mass spectrograph equipped with an α\alpha-TOF detector. The Ra isotopes were produced as fusion-evaporation products in the 51^{51}V+159^{159}Tb reaction system and delivered by the gas-filled recoil ion separator GARIS-II at RIKEN. The α\alpha-TOF detector provides for high-accuracy mass measurements by correlating time-of-flight signals with subsequent α\alpha-decay events. The masses of 206^{206}Ra and 207g,m^{207g,m}Ra were directly measured using a multi-reflection time-of-flight mass spectrograph equipped with an α\alpha-TOF detector. A mass excess of ME = 3538(15) keV/c2^2 and an excitation energy of Eex_{\rm ex} = 552(42) keV were determined. The α\alpha-decay branching ratio of 207m^{207m}Ra, bα\alpha = 0.26(20), was directly determined from decay-correlated time-of-flight signals, and the reduced alpha width of 207m^{207m}Ra was calculated to be δ2\delta^2 = 50+62-41 keV from the branching ratio. The spin-parity of 207m^{207m}Ra was confirmed to be JπJ^\pi = 13/2^- from decay correlated mass measurement results.

Keywords

Cite

@article{arxiv.2108.06245,
  title  = {Alpha-decay-correlated mass measurement of 206,207Ra using an $\alpha$-TOF detector equipped MRTOF-MS system},
  author = {T. Niwase and M. Wada and P Schury and P. Brionnet and S. D. Chen and T. Hashimoto and H. Haba and Y. Hirayama and D. S. Hou and S. Iimura and H. Ishiyama and S. Ishizawa and Y. Ito and D. Kaji and S. Kimura and J. Liu and H. Miyatake and J. Y. Moon and K. Morimoto and K. Morita and D. Nagae and M. Rosenbusch and A. Takamine and T. Tanaka and Y. X. Watanabe and H. Wollnik and W. Xian and S. X. Ya},
  journal= {arXiv preprint arXiv:2108.06245},
  year   = {2021}
}