Preliminary results on nuclear isomer production via laser-driven bremsstrahlung irradiation at ELI-NP-1PW

Abstract

In this contribution we present the preliminary results regarding laser-driven nuclear isomer-production obtained during the commissioning of 1 PW-E7 experimental area at ELI-NP. The study of nuclear isomers production and their photoreactions has been a subject of lasting interest in the nuclear physics community. Nuclear isomers play a crucial role in the creation of the elements in the Universe and in controlled nuclear energy release. The high-intensity and ultra-short pulsed lasers, available at ELI-NP facility, have a great advantage for studying isomeric states with life-times that are impractical to investigate by using conventional accelerator or nuclear reactor experiments. The 1 PW high-power laser was focused on 1 mm supersonic gas jet (mixture of 98% He-2% N₂) at laser pulse energy on target of E${}_{LonT}$≈20 J in order to generate electron bunches via the Laser Wakefield Acceleration. Electrons with energies up to 500 MeV were obtained at laser intensity on target of 2-2.5x10²⁰ W/cm² and 10 bar backing pressure of 98% He-2% N₂ gas jets. Intense bremsstrahlung radiation was further generated by impinging the laser-accelerated-electrons on a 10-mm-thick ¹⁸¹Ta photo-converter placed before the natural In target. Several indium isomers were produced using the laser-driven bremsstrahlung irradiation, e.g. ${}^{113m}$In, ${}^{115m}$In and ${}^{116m}$In.