Menlo Research Laboratory Uranium Test Kit (ca. 1952)
The Uranium Test Kit was manufactured, sometime in the early 1950s, by the Menlo Research Laboratory of Menlo Park, California. The Uranium Tester, the black plastic chamber with the projecting tube seen in the photo above left, was an accessory that had to be purchased separately.
The manufacturer noted that a standard radiation detector (e.g., Geiger counter) cannot distinguish uranium from other sources of natural radiation. The purpose of this kit is to provide a method to test ore samples specifically for uranium.
The method involves heating a bead wire (see plastic vial in photo above left) using the "super jet blow torch" (in the lower right corner of the photo above left). The heated wire is dipped into the sodium fluoride powder and then reheated so that a molten ball of NaF is formed on the tip of the wire. This bead is brought in contact with the ore to be tested and then reheated so that the molten bead is well mixed. After the bead cools, its fluorescence is studied under UV light. The process is then repeated using the lithium fluoride. If a lemon-yellow fluorescence is seen with both beads, uranium is present.
The Uranium Tester accessory allows the fluorescence of the beads to be investigated in daylight. The beads are inserted into the bottom of the chamber and the Tester is positioned so that sunlight is directed onto the circular UV filter on the top of the chamber. Fluorescence is observed by looking through the tubular eyepiece. The manufacturer sold a fancier version of the Tester known as the Menlo Fluoretor. The latter was pretty much the same except that it had a hand-held UV light source that was connected to the chamber (see accompanying photo).
The following advertisement is from the February 1952 issue of Science and Mechanics. In the photo, you see the "super jet blow torch" in use. A Dry Fuel disk has been placed on the circular tray of the torch and lit. The intensity of the flame is being increased by the air blown through the "sanitary blow tube."
Menlo Uranium Test Kit instructions. No date.