Precise measurement of energy of the first excited state of ¹¹⁵ Sn (E _exc ≃ 497.3 keV)

Abstract

Single beta decay of 115 In to the first excited level of 115 Sn (Eexc 497.3 keV) is known as β-decay with the lowest Q β value. To determine the Q β precisely, one has to measure very accurately the Eexc value. A sample of tin enriched in 115 Sn to 50.7% was irradiated by a proton beam at the U-120 accelerator of INR, Kyiv. The 115 Sb radioactive isotope, created in the 115 Sn(p,n) 115 Sb reaction, decays with T 1/2 = 32 min to 115 Sn populating the 497 keV level with 96% probability. The total statistics of ∼10 5 counts collected in the 497 keV peak in a series of measurements, the exact description of the peak shape and the precisely known calibration points around the 497 keV peak allowed to obtain the value Eexc = 497.342(3) keV, which is the most precise to-date. This leads to the following Q * β value for the decay 115 In → 115 Sn * : Q * β = 147 ± 10 eV.

Precise Q value measurements of $^{112,113}$Ag and $^{115}$Cd with the Canadian Penning trap for evaluation of potential ultra-low Q value $β$-decays

“…> 1 keV) to be considered as an UL decay, ruling both out as potential UL Q value β-decays. Our Q value measurement of 113 Ag indicated a 69 (17) keV discrepancy compared to data from the AME2020. This result ruled out the potential UL Q value decay to the 1/2 + , 2015.6 keV state in 113 Cd, but indicated a new potential UL Q value branch to the 1/2 + at 2080 (10) keV.…”

“…[16] and E[ 115 Sn(3/2 + )] = 497.342(3) keV from the recent measurement of Ref. [17]. 2 This Q value remains the same in the most recent 2020 update to the Atomic Mass Evaluation (AME2020) [22].…”

Direct measurement of the mass difference of As72−Ge72 rules out AsZhuang1, Eronen2, Roubin3 et al. 2021Phys. Rev. C180601View full textAdd to dashboardCite

“…The Q value of this branch was independently measured by Penning trap measurements at Florida State University [22] and at the University of Jyväskylä [23]. With the accurately measured excitation energy of the first excited state of 115 Sn from [24], the Q value of this branch was determined to be 0.147 (10) keV.…”

High-precision electron-capture $Q$ value measurement of $^{111}$In for electron-neutrino mass determination

“…The betadecay value has been further refined to 0.155 (24) keV independently by Mount et al [26]. The value of this branch was recently determined to be 0.147 (10) keV with the accurately measured excitation energy of the first excited state of 115 Sn [27]. A low -value − -decay transition from the 7/2 + ground state of 135 Cs to the second excited state of 135 Ba, with = 11/2 − , was recently investigated at JYFLTRAP.…”