A Scintrex-manufactured Model 409M beta survey meter. The monitor, which stands 20 cm in height and 18 cm in length, has a built-in stand that serves to shield the user’s hand from the beta fields being measured. The window at the end, which is protected with a removable cover, is 2 cm in diameter. Technical information on the instrument has been difficult to source, but the detectors have been identified to be silicon diodes. The instrument has two selectable ranges. The low range is from 0 to 2 Gy/h (200 rads/h or 200 “rem/h”). The high range extends this to 20 Gy/h (2000 rads/h or 2000 “rem/h”). Scintrex, a small company in Concord Ontario, were a supplier of a number of models of radiation monitoring equipment.
