Laser-induced photo transmutation of 126Sn – A hazardous nuclear waste product-into short-lived nuclear medicine of 125Sn

Relativistic electrons, generated in the interaction of an ultra-intense laser pulse with plasma in front of a high-Z solid target, when passing near the nuclei of the solid target produce several MeV highly collimated Bremsstrahlung gamma beam, which can be used to induce photo-nuclear reactions. In this work the possibility of photo-induced transmutation ( γ n ) of a nuclear waste of 126 Sn with a half-life of 100,000 years into 125 Sn with a half-life of 9.64 days was investigated for the first time. Calculations based on the available experimental data show that the Bremsstrahlung γ beam generated by irradiating a 2 mm thick tantalum target as a converter with 10 20 W cm - 2 μ m 2 and 10 Hz table-top laser for an hour can produce 293 Bq activity in a 1 cm thick 126 Sn sample placed directly behind it. The remarkable feature of this work is to evaluate the optimal laser intensity to produce maximum activity of 2257 Bq which is 1.18 × 10 21 W cm - 2 μ m 2 . The selective excitation of nuclear resonance states are discussed by studying the rate equations and calculating the Einstein coefficient. According to our calculations, we achieve relative decay rate of 0.0025, for two possible decay channels. Our results show the most probable channel for this mechanism which has a good agreement with direct excitation process.