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15 × 15 × 29 cm

This Cathode Ray Tube Gun Assembly is a display version of the interior of an EMI cathode ray tube. It was used as part of a display in the 1970’s and 80’s, and has its principal parts labelled. It is mounted on a wooden base which is engraved with ‘P.L.U.Q.’ indicating its use in the UQ Physics labs.

A CRT Gun is the electron-emitting section of a CRT, and generates, focuses and deflects a beam of electrons. Within the vacuum of the tube there is a cathode that can be heated so as to produce a stream of electrons via thermionic emission. These electrons, once ejected from the cathode, are guided using electrostatic fields (rather than magnetic forces as in a television tube) between opposing plates to repel and guide the electron stream. In this CRT Gun, there are two sets of plates which are labelled ‘X Plates’ and ‘Y Plates’ and are used to deflect the electrons in the horizontal and vertical directions.

This stream of electrons then collides with the screen of the CRT, which is coated in a layer of phosphor. As the electrons strike the phosphor, it emits light.

This item is part of the UQ Physics Museum Oscilloscopes Tour
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