• The Ludlum Model 15 detects and measures alphas, betas, gammas, and neutrons. A GM detector can be selected by the user to obtain alpha-beta gamma readings. The instrument's neutron countrate measurement is provided by a 3He proportional detector that is outfitted with a removable moderator.
• The ratemeter is a four-decade, analog meter designed with an aluminum cast instrument housing, incorporating a separate battery compartment and accompanying metal handle. This design delivers industrial robustness and quality, promoting long-lasting protection and instrument life. The front-panel controls include a rotary switch for selecting the four-decade range, instrument shut-off, and battery test, an audio on/off switch, a fast/slow response switch, a GM/Neutron Detector switch, a count reset, and high-voltage test pushbutton. The Model 15 is a complete turn-key system and includes two "D" cell batteries.

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