Miskun, Ivan; Dickel, Timo; Mardor, Israel; Hornung, Christine; Amanbayev, Daler; San Andres, Samuel Ayet; Bergmann, Julian; Ebert, Jens; Geissel, Hans; Gorska, Magdalena; Greiner, Florian; Haettner, Emma; Plaß, Wolfgang R.; Purushothaman, Sivaji; Scheidenberger, Christoph; Rink, Ann-Kathrin; Weick, Helmut; Bagchi, Soumya; Constantin, Paul; Kaur, Satbir; Lippert, Wayne; Mei, Bo; Moore, Iain; Otto, Jan-Hendrick; Pietri, Stephane; Pohjalainen, Ilkka; Prochazka, Andrej; Rappold, Christophe; Reiter, Moritz P.; Tanaka, Yoshiki K.; Winfield, John S. (SpringerSpringer Berlin Heidelberg, 2019-09-04)
A novel method for simultaneous measurement of masses, Q-values, isomer excitation energies, half-lives and decay branching ratios of exotic nuclei has been demonstrated. The method includes first use of a stopping cell as an ion trap, combining storage of mother and daughter nuclides for variable durations in a cryogenic stopping cell (CSC), and afterwards the identification and counting of them by a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). We utilized our method to record the decay and growth of the <sup>216</sup>Po and<sup> 212</sup>Pb isotopes (alpha decay) and of the <sup>119m2</sup>Sb isomer (t<sub>1/2</sub>=850±90 ms) and <sup>119g</sup>Sb isotope (isomer transition), obtaining half-lives consistent with literature values. The amount of non-nuclear-decay losses in the CSC up to ∼10 s is negligible, which exhibits its extraordinary cleanliness. For <sup>119</sup>Sb isotopes, we present the first direct measurements of the mass of its ground state, and the excitation energy and decay branching ratios of its second isomeric state (<sup>119m2</sup>Sb). This resolves discrepancies in previous excitation energy data, and is the first direct evidence that the <sup>119m2</sup>Sb isomer decays dominantly via γ emission. These results pave the way for the measurement of branching ratios of exotic nuclei....