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Detector, Electron Multiplier


Display Status:

This object is on display in the Boeing Aviation Hangar room at Steven F. Udvar-Hazy Center in Chantilly, VA.

Detector, Electron Multiplier

Collection Item Summary:

Bendix manufactured this open cathode electron multiplier and detector circa early 1960s, typical of detectors flown on early OSO spacecraft. The cathode is not enclosed in a glass or other insulating envelope since it was designed to work in the vacuum of space. A sufficiently energetic UV photon striking the cathode at the entrance grid of the device results in the release of one or more electrons. The first of a series of permanent magnets then directs the emitted electrons onto a strip of specially coated glass. This results in the release of a large number of secondary electrons. Repetition of this process leads to a cascade of charge with the resulting current gain as high as 10 million fold.

The detector was transferred to NASM by NASA (GSFC) in 1995.

Collection Item Long Description:

Data Source

National Air and Space Museum


Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


Credit Line

Transferred from the National Aeronautics and Space Administration


Overall - metal and glass, electronics


3-D: 8 x 3.3 x 2.9cm (3 1/8 x 1 5/16 x 1 1/8 in.)

Country of Origin

United States of America



Inventory Number