Elemental and isotopic effects in neutron induced desorption from surfaces

Recoil of atoms following (n, γ) reactions may cause them to desorb from the surface. This effect is studied in irradiation experiments under high thermal neutron flux for gold and indium, utilizing prepackaged ampules under vacuum. The role of thermal desorption is demonstrated, through a comparative study of the behavior of different elements under identical conditions. Precise measurements of the populations of indium isotopes were carried out, revealing large 194 Ir 192 Ir differentiation. This is shown to be related to the temporal history of desorption during the irradiation, and provides additional meaningful information about the process.