Identification of new isomers in $$^{228}$$Ac: impact on dark matter searches

We report the identification of metastable isomeric states of $$^{228}$$ 228 Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the $$\beta $$ β -decay of $$^{228}$$ 228 Ra, a component of the $$^{232}$$ 232 Th decay chain, with $$\beta $$ β Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of $$^{228}$$ 228 Ra as well as the relative abundance of $$^{232}$$ 232 Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.

Isomeric Ratios 109m,gPd in the (γ, n) and (n, 2n) Reactions

The method of induced activity of the investigated cross-sections of excitation of isomeric states in the 110Pd(y,n)109m,gPd and 110Pd(n,2n)109m,gPd reactions in the energy range 12–35 MeV is studied. The experimental results are compared with those of calculations carried out using the software package TALYS-1.6.