WHOLE-BODY PERSONNEL MONITORING VIA IONIZATION DETECTION

A project between Fernald EMP and LANL is to field a monitor for the d etection of alpha-emitting contamination on a human body. Traditional personnel monitoring for alpha emitters involves either frisking with a probe or pressing against large detectors in order to overcome the s hort range of alpha particles. These methods have a low alpha collecti on efficiency, and can miss contamination on; less accessible surfaces . We have investigated the sensitivity and practicality of measuring t he entire subject simultaneously using the technique of ionization mon itoring. The goal is to create a booth that personnel step into quickl y during egress from radiological facilities. The detection technique relies on a breeze of air passing over the subject. Alpha emission pro duces copious ions In the ambient air which are transported by the air current to an ion collector, resulting in a small electrical current proportional to the amount of contamination. Results indicate a conser vative sensitivity of 3000 disintegrations per minute localized to one of five areas of the body in a measurement lasting less than 2 minute s.