Victoreen Models 252 and 262 Indirect Reading Pocket Chambers (ca. late 1940s and 1950s)
The following photographs show what I believe to be a Model 252 (top) and a Model 262 (bottom) indirect-reading pocket chamber manufactured, probably in the late 1940s and 1950s, by the Victoreen Instrument Company of Cleveland, Ohio. Intended to be used with the Victoreen Minometer charger-reader, they measured doses in the 0-200 mR range.
As best as I can reconstruct it, the Model 242 chamber was used with the Minometer when the latter was first introduced (in 1940 or so). Shortly after the war, ca. 1946, the Model 242 was replaced by the Model 252. The latter, in turn, was replaced by the Model 262 sometime around 1951.
It would seem that one minor difference between the Models 252 and the 262 is that the pocket clip was positioned right at the end of the Model 252 barrel but further down on the original version of the Model 262. In later (e.g., 1960s) versions of the Model 262, the clip was once again positioned right at the end of the barrel.
The photograph to the right shows the charging contact with the protective aluminum cap removed. As was the case with the Landsverk pocket chambers, the protective cap had a groove machined around it. This meant that the person responsible for reading large numbers of these chambers could remove or replace the caps while using only one hand by slipping the groove into the slot of a tabletop jig.
Size: 4.5” long and 0.5” in diameter
Chamber: Graphite loaded paper
The cap on the top of the Model 252 is stamped (on three separate lines): D, 3906, 3A. The top of the Model 262 is stamped S, 5277, 3A.