The energy spectra of 235U atoms sputtered from a 93% enriched235U metal foil and a hot pressed 235U02 pellet by an 80 keV 40Ar+beam have been measured in the range 1 eV to 1 keV. The measurementswere made using a mechanical time-of-flight spectrometer in conjunctionwith the fission track technique for detecting 235U. The design andconstruction of this spectrometer are discussed in detail, and itsoperation is mathematically analyzed.
The results of the experiment are discussed in the context ofthe random collision cascade model of sputtering. The spectrum obtainedby the sputtering of the 235U metal target was found to be well describedby the functional form E(E+Eb)-2.77, where Eb = 5.4 eV. The 235U02target produced a spectrum that peaked at a lower energy (~ 2 eV) anddecreased somewhat more rapidly for E ≳ 100 eV.
