A nuclear-detection method for sulfur in thin films

Abstract

A method is described for identifying the presence of sulfur in thin films on coins through the use of the S 32(d,p)S 33 reaction. A sample film was bombarded with a 2.0 MeV deuteron beam from a Van-de-Graaff accelerator, and a high resolution solid-state detector, located at 135° with respect to the incident beam direction, was used to detect the protons emitted from the target. The method is non-consuming and has proven to be simple and sensitive; sulfur films with surface densities of 10 −7 g/cm 2 are estimated to be easily identifiable. In the present work, the area of the sample film bombarded by the beam was approximately 0.5 mm 2. No attempts were made to determine the ultimate sensitivity of the method. The technique described here should prove useful also for other combinations of thin film and backing materials. For each case, however, choice of the appropriate nuclear reaction will depend on considerations of interfering radiation from the backing materials and from likely contaminants.