Type T.Q.V. Chalk River electroscope

Artifact Number:



One of a set of beta electroscopes developed and patented at Chalk River in the 1940s under the leadership of Hugh Carmichael for the accurate measurement of radioactivity. This Type T.Q.V., Serial No. 19, specimen is believed to be a precursor to the more sophisticated and polished Type T.Q.Q.B. models (Artifacts 2023-015 and 2023-016). It is built on a 21 cm diameter circular, adjustable base and stands 35 cm tall. Partial disassembly led to the discovery of the hemispherical copper base on which a ~1mm thick mounting post exits from which, under “just-right” lighting, the crucial, ~6 micron thick, gold-plated, quartz indictor fibers are mounted. This unit bears an NRX number tag of T 4057.


electroscope; radiation detectors
Associated artifacts:
See also artifacts 2023-014 to 2023-016 and 2023-018

This older model electroscope was one of two of similar vintage.  The other (2023-018), lacked a nameplate indicating Type or serial number.  This one seemed more amenable to partial disassembly for investigation.  The thin, delicate quartz fibers were completely missed on the first disassembly and only showed up when the photos were more carefully examined.  A second round of investigation with careful lighting positioning allowed them to be observed.

This electroscope differs from the Type T.Q.Q.B. models in that a high-voltage connector is provided at the bottom of the experimental chamber.

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