These are three Anton 314 Geiger Mueller counter tubes of the type used in Explorers I, II, and III in James Van Allen's cosmic-ray payloads. The right-hand counter in primary image is in original form as received from Anton. The other two, numbered 17 and 51, are as prepared for a satellite package with mounting ring and high-voltage terminal encapsulated (potted). These are components from a payload inventory originally intended for the State University of Iowa package to be flown on Vanguard and the early Explorer satellites. They include components in George Ludwig's possession since they were built in the late 1950s. Donated by Dr. George Ludwig in 2006.
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This object is not on display at the National Air and Space Museum. It is either on loan or in storage.