  A method is reported for measuring the thickness and uniformity of thin films
of solidified gas targets. The energy of alpha particles traversing the film is
measured and the energy loss is converted to thickness using the stopping
power. The uniformity is determined by measuring the thickness at different
positions with an array of sources. Monte Carlo simulations have been performed
to study the film deposition mechanism. Thickness calibrations for a TRIUMF
solid hydrogen target system are presented.
