摘要

Traditional alpha contamination monitors have a low detection efficiency, and can miss contamination on less accessible surfaces, uneven surfaces and piping inner surfaces etc. New measuring equipment with alarming system designed to be used to solve these problems is discussed in this paper. This system uses Long-Range Alpha Detection (LRAD) technology, which monitors alpha contamination by measuring the ionization in ambient air formed by alpha particles. The whole monitor system contains an iron chamber detector, a high quality MCU system, and adopts Sigma-Delta signal processing technology. It is designed to be used primarily in the field and in the laboratory measurements. The monitor is battery-powered and can operate continuously for up to ten hours. The test result indicates that the available detect length L is more than 2m, the relative detect efficiency eta is better than 40%. This kind of alpha surface contamination monitor has been well used at some radiation site and has been proven to meet the needs.