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A novel method for the measurement of half-lives and decay branching ratios of exotic nuclei
Ist Teil von
The European physical journal. A, Hadrons and nuclei, 2019-09, Vol.55 (9), p.1-12, Article 148
Ort / Verlag
Berlin/Heidelberg: Springer Berlin Heidelberg
Erscheinungsjahr
2019
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
.
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
216
Po and
212
Pb isotopes (alpha decay) and of the
119m2
Sb isomer (
t
1
/
2
=
850
±
90
ms) and
119g
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
119
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 (
119m2
Sb). This resolves discrepancies in previous excitation energy data, and is the first direct evidence that the
119m2
Sb isomer decays dominantly via
γ
emission. These results pave the way for the measurement of branching ratios of exotic nuclei.