A Ludlum, Model 44-9, radiation detector that can be used to detect alpha, beta and gamma radiation. The detector, which has an overall length of 27 cm, can be used with a wide range of counters and has an operating voltage of 900 V. The mica window of the halogen-quenched, Geiger-Mueller tube has an active area of 15.5 square centimetres. This instrument was used by the Radiation and Industrial Safety (RIS) group at Chalk River, and is still widely used today.
