Model L3TSM-56 "Oremaster" Super Geiger Counter (ca. 1956)
The “Oremeaster” was manufactured by White’s Electronics of Sweet Home Oregon.
It employs three thin walled GM tubes that are housed inside the case at the front end of the instrument. To permit betas to reach the tubes, the case has fifteen ¾” cloth covered holes on the front end and ten such holes on the bottom front. The detector output is indicated either by the meter reading or an audio signal, but not both. When the speaker is employed and the “High” setting selected, the audio output registers the signals from all three tubes. If the “Low” setting is chosen, the output from only one tube is registered. The operating instructions strongly recommend the use of the audio output when working in rough terrain or snake country because it might then be unsafe to watch the meter. They make the point that while a rattlesnake is “not usually aggressive, to step on him is to make him fighting mad.”
The assigned date of 1956 is based on the model,
number which ends in 56, and the fact that very similar models, but not
this one, were described in the AEC instrument supplement from 1954. A
calibration sticker on the unit is dated
Detector: three thin walled GM tubes. Jack for external probe
Range: 0 – 0.2, 0 – 2.0, 0 – 20 mR/h
Audio: speaker, no headphone capability.
Size: 4.75” x 17” x 4”
Batteries: two 1.5 volt, one 22.5 volt and two 90 volt
The “Oremaster” operating manual comes with the following “Treasure Hunter’s Code of Ethics”
Operating Instructions for Model L3TSM-56 Oremaster Super Geiger Counter, no date.
Copyright 1999, Oak Ridge Associated Universities