Measurement of Alpha Particle Energies and Half-lives in Air

The physical explanation of alpha particle decay is derived from equation for quantum mechanical tunnelling and generally agrees with the Geiger-Nuttall empirical law relating the alpha particle kinetic energy to the half-life of the isotope from which the alpha particle is emitted. Measurements in the intermediate and advanced lab of a variety of half-lives and alpha particle energies can generate data for a Geiger-Nuttall empirical law can be made using a Passivated Implanted Planar Silicon (PIPS) detector in air. The isotopes from the radon decay from natural uranium and thorium are collected electrostatically on the front surface of the detector and the spectra of the emitted alpha particles can be measured as a function of energy and time, during the collection of the isotopes or after collection. Use of the Bateman equations helps to determine the half-lives of some of the decay products. Results from the measurements will be presented.