An efficient two-dimensional scanner for beta emitters

A line scanner has been developed which permits the localization and real time quantification of β emitters on a flat two-dimensional surface. With a well maintained detector the spatial resolution is 2-3 mm (full width half-maximum) in each dimension with an overall detection efficiency (for a 20 cmx5 cm area) of about 0.5%. The β particle is detected in a pair of linear position sensitive proportional counters, one located behind the other, and the origin of the decay β is obtained by ray tracing in one dimension and scanning in the other. By this technique a large solid angle can be accepted without substantial degradation of position resolution. The device can also be used as a one-dimensional detector with an overall efficiency of about 10%. Applications have been made to the detection of β's from the decay of 13N and 14C. (Auth.)