Long-range alpha detector.

Historically, alpha-particle detectors have been limited by the very short range of alpha particles in air. This results in a number of problems inherent to alpha contamination detectors, such as relatively poor sensitivity, geometry limitations, and inefficient monitoring techniques. In this paper, we document tests of a new long-range alpha detector. The charges generated by the interaction of alpha particles with air can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions and, hence, detects the alpha decays.