Ranges in Tungsten of⁹⁹Mo and¹³²Te Fragments from the Thermal Neutron Fission of²³⁵U

The median ranges of 99Mo, 132Te were measured by collecting uncollimated fission fragments from the thermal neutron fission of a thin 235U target in tungsten catchers. Depth distributions of these radioactive species were obtained by sequential sectioning of the tungsten catchers, radiochemical isolation of the fission fragments in each section and subsequent radioactive assay. The anodising and stripping technique of McCargo et al. for forming and removing uniform surface films of known thicknesses from tungsten was used in the sectioning. The median ranges obtained from these depth distributions were 10.03±0.06, 8.60±0.06 mg/cm2 for 99Mo, 132Te respectively.