The Application of Silicon Detectors to Alpha Particle Spectroscopy

The sensitivity for detection of low abundance groups in an alpha spectrum was found to be limited primarily by a low energy tail in the pulse height distribution. The effects of scattering and source preparation on the magnitude of this tail were experimentally investigated. A theoretical lower limit of sensitivity for low abundance groups was calculated from consideration of scattering processes in the crystal. Background contamination in new detectors and the increase in background due to the collection of recoil nuclei was studied. Methods for minimizing the increase in background are suggested. A chamber, designed from a consideration of the above results, was constructed and used for the detection and measurement of low abundance groups in the alpha spectra of U234 and the actinium decay series.