First direct measurement of α decay half-life of ¹⁰⁴Te

Nearly all alpha emitting nuclei are found with N>82, yet an island of alpha decaying nuclei above the doubly-magic, self-conjugate, ¹⁰⁰Sn was found as the result of the N=50 and Z=50 shell closures. Neutron-deficient tellurium (Z=52) alpha-emitters were first discovered by Macfarland and Siivola [1], postulating that increased proton-neutron correlations lead to an increase in alpha-particle preformation. They coined the term “super-allowed” alpha-emitters, with enhanced preformation culminating in the decay of ¹⁰⁴Te to ¹⁰⁰Sn. Due to increased alpha preformation, ¹⁰⁴Te is predicted as the fastest alpha-emitting nucleus when accounted for decay energy. Two events of ¹⁰⁴Te were measured by Auranen et al. Despite limited statistics, the authors placed an upper limit of 18 ns on the half-life via the decay chain of ¹⁰⁸Xe [2]. Due to the short half-life, electromagnetic separation is unavailable for identifying ¹⁰⁴Te nuclei. Thus, the decay of ¹⁰⁸Xe remains the only option for studying the decay of ¹⁰⁴Te. This work reports the measurement of the decay chain of ¹⁰⁸Xe to ¹⁰⁴Te to ¹⁰⁰Sn, produced via the projectile fragmentation of ¹²⁴Xe at RIKEN Radioactive Ion Beam Factory (RIBF). Utilizing a fast-response scintillator-based charged-particle detector [3], we measured the decay properties of ¹⁰⁴Te. The results will be compared with the results of [2] and numerous theoretical predictions.



[1] R. Macfarlane and A. Siivola, PRL 14, 144 (1965)

[2] K. Auranen, et al. PRL 121, 182501 (2018)

[3] Y. Xiao, et al. PRC 100, 034315 (2019)