Efficient production of the nuclear isomer ^{93m}Mo with laser-accelerated proton beam and its astrophysical implication on ^{92}Mo production

Abstract

Nuclear isomers play a key role in the creation of the elements in the universe and potentially have significant applications related to the controlled release of nuclear energy on demand. Particularly, ^{93m}Mo is a good candidate for studying the depletion of nuclear isomers via nuclear excitation by electron capture. Therefore, it is necessary to explore the efficient approach of ^{93m}Mo production. In this paper, we experimentally demonstrate an efficient production of ^{93m}Mo via ^{93}Nb(p,n) reaction induced by an intense laser pulse. Employing the picosecond-duration, 100 J laser pulse, the ^{93m}Mo isomer at 2425 keV (21/2^{+}, T_{1/2}=6.85h) is generated with a high yield of 1.8×10^{6} particles/shot. The resulting peak production efficiency reaches 10^{17} particles/s, which is at least five orders of magnitude higher than that obtained using the classical accelerator. The impacts of the production and destruction of ^{93m}Mo to the astrophysical p-nuclide ^{92}Mo are studied. It is found that the ^{93}Nb(p,n)^{93m}Mo reaction is an important production path of ^{93m}Mo, which could further influence the production of ^{92}Mo. In addition, a direct measurement of the (p,n) reaction rate is proposed using the laser-induced proton beam of which the energies follow the Maxwell-Boltzmann distribution well. It is believed that the laser-induced proton beam opens an avenue for the production of nuclear isomers with high peak efficiency used for the studies of p-nuclei nucleosynthesis.