The Alpha Contamination Goggles developed by BIC allow the user to see radioactive smears and discharges, making them easier to detect and deal with accordingly. The goggles combine the latest improvements in night vision technology with the phenomenon first observed early last century by Ernest Rutherford, whereby flashes of light are given off by zinc sulphide when struck by alpha particles.
A potentially contaminated surface or object is sprayed with a scintillant that temporarily adheres to the surface. The user then switches over to safe lighting and puts on the goggles. The areas of alpha contamination are then clearly seen with one eye as patches or spots of light. High alpha activity is seen as brighter sources of light. For QA purposes the goggle images can be stored on a small video recorder mounted on a belt and video footage analysed or archived. Remote installed cameras can be supplied where conditions are difficult or hazardous.
The goggles have been developed for use in many different conditions, but are particularly suited to looking for hot spots during decommissioning.
BIC spokesman Mike Scott said that the system is particularly good at seeing hot spots in difficult to reach places, whereas an alpha probe has to be totally flat to the surface to get good results. In addition, a probe placed directly on a low activity alpha source produces one count every ten seconds. The same contaminant appears as a steady light source visible from 5-6ft away using the BIC Alpha Goggles. The system is therefore most useful as a means to find contamination. Once detected, conventional equipment can be used to quantify and qualify the contamination.
Using the goggles, alpha contamination as low as 30 becquerels per square centimetre can be seen. BIC are currently developing scintillant that has a slower prolonged flash, making even lower levels of contamination visible to the human eye.