Measurement of surface alpha contamination using electret ion chambers.

Electret ion chambers are inexpensive, light-weight, commercially available, passive charge-integrating devices for accurate measurement of different radiations. Performance of electret ion chambers for surface alpha contamination measurement was evaluated. Ion chambers of two types and electrets of three thicknesses were used for the study. Calibration of the electret ion chambers was performed using reference alpha standards of different energies and radioactivities. Effects of various parameters such as chamber dimensions, electret thickness, alpha particle energy, position of alpha source from the chamber centerline, source localized or uniformly distributed, level of alpha contamination, Mylar window covering the chamber, and ambient radon and gamma radiation on the response of the electret ion chambers were determined. Suitable combinations of chambers and electrets to measure surface alpha contamination were determined.