Halross Model 939 Scintillometer (ca. 1953-1955) |
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This is the Model 939 "Scintillometer" made by Halross Instruments Corp.
Ltd. of Winnipeg, Canada. The Model 939 is remarkable for being one
of the very first commercially available gamma scintillators -
it first came on the market in 1950. This example is a slightly later
version of the "Scintillometer" that was probably manufactured in
1953-1955. I believe that Halross went bankrupt sometime
around 1955 and sold much of their operation
to Canadian Aviation Electronics Ltd. The following is a quote from a product notice in the June 1950 issue of Nucleonics: "A gamma-ray spectrometer feature of the Model 939 Scintillometer allows the operator to distinguish between thorium and uranium ore deposits, and will indicate the uranium concentration in an ore containing both radioactive minerals. Utilizing the scintillation principle, the portable battery-operated instrument is housed in an aluminum alloy case measuring 3 1/2 by 11 by 13 in. A removable probe is contained in the lower section of the case. The electronic circuit is protected against vibration, shock, temperature and humidity." One thing I would like to know more about is the relationship between Halross and Nuclear Enterprises Ltd., another Winnipeg manufacturer of scintillators. According to Grigg's "Trail of the Invisible Light," Nuclear Enterprises Ltd. "deleloped the first scintillation counter for field use, and soon adopted it as an airborne instrument, which was flown exclusively by the USAEC for several years." This would have in 1949 or 1950. What is curious is the fact that Halross's main product line was in the agricultural area (e.g., seed counters and the Model 919 grain moisture meter), not radiation detectors. That such a company would produce a gamma scintillator at the same time and in the same town that Nuclear Enterprises produced what might be the world's first gamma scintillator, suggests some sort of connection between the two companies. Even the canvas case first used by NE and the Halross case (see below) are remarkably similar.
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Is it possible that Nuclear Enterprises had Halross manufacture the meter for them? Detector: NaI detector Meter scale: 0 – 120, 0-300, 0-600, 0-1200, 0-6000 counts per second. Size: 3.5" x 11" x 13" Batteries: References
Halross Instruments. Models 939 and 939A Scintillometers Operating Instructions. Revised 1952. Product notification. June 1950, Nucleonics, page 82. Gamma Ray Detector. 1950 J. Sci. Instrum. 27 340-340. |
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