93mMo Production and Induced Depletion Using Laser-Accelerated Heavy-Ion Beams

摘要: The isomer depletion of 93mMo has potential applications in high-energy-density storage, nuclear batteries, and gamma-ray lasers. Laser-accelerated heavy-ion beams offer great advantages in high peak current and large instantaneous particle flux, and are expected to provide a novel route for the efficient production of 93mMo and the study of isomer depletion. This work theoretically investigates the production of 93mMo in inverse kinematics with laser-accelerated heavy-ion beams and the subsequent induced depletion in a carbon stopping target. The 93mMo yields from four typical inverse-kinematics reaction channels, 4He(91Zr, 2n), 7Li(90Zr, p3n), 9Be(88Sr, 4n), and 12C(86Kr, 5n), are analyzed. Among these reaction channels, the 4He(91Zr, 2n) reaction gives the highest emission yield, reaching 9.13 × 10^4 ions/nC at optimized ion energy and reaction target areal density. Theoretical analysis shows that the 93mMo depletion is dominated by inelastic nuclear scattering rather than nuclear excitation by electron capture. The resulting depletion probability is estimated to be on the order of 10^-6, which is in good agreement with the experimental observation. Further simulations show that the 4He(91Zr, 2n) reaction can induce a depletion yield as high as 1.17 × 10^-1 events/nC when the produced 93mMo ions are stopped in the carbon target, which is increased by a factor of 6–20 compared to the other selected channels. This is because the emitted 93mMo ions have a high yield and carry sufficient kinetic energy, leading to a relatively large depletion probability. As a result, the 4He(91Zr, 2n) reaction can be regarded as a favorable channel for 93mMo isomer depletion experiments driven by laser-accelerated heavy-ion beams. In addition, a preliminary experiment on laser acceleration of Zr ions was performed at the Shanghai Superintense Ultrafast Laser Facility. A Zr30+ ion beam with a cutoff energy of about 850 MeV was obtained, which could provide a basis for future experimental campaigns on laser-driven 93mMo production and induced depletion.