This is a gas gain ion chamber ionization detector. The lithium fluoride window in this detector was designed to be transparent to radiation in the range from 1050 to 1300 Angstroms. The charges generated by the impact of the photons on the interior gas then traveled to the oppositely charged electrode. Additional collisions of the ions and electrons with filling gas on their way to the electrodes generated more charges and in effect amplified the signal.
This artifact is part of a collection of high energy detectors from the Naval Research Laboratory (see Catalogue#s 19880001000-19880017000). It was transferred to NASM in 1987.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.