Use of infinitely thick source alpha particle pulse height distributions in the determination of individual specific alpha activities

A method is presented in which material containing a complex mixture of alpha emitting radionuclides might be analyzed with minimal sample preparation and the individual specific activities of each alpha emitting species found. A theoretical relationship describing the pulse height distribution of an infinitely thick source of alpha activity is developed. This relationship is then fit to uranium and thorium oxide pulse height distribution data obtained with a PIPS detector/MCA counting system, confirming the validity of the theoretical pulse height distribution. The method does not require complex and time consuming sample preparation common to conventional alpha spectroscopy. Results obtained from fits to the pulse height distributions are in agreement with the specific alpha activities of the oxides.