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Resnatron cathode assembly
Resnatron cathode assembly

Resnatron cathode assembly

Date1943-1944
Inventory NumberRS0080
ClassificationResnatron
Subject
    Cultural Region
      Place of Origin
        Dimensions73 x 12 x 12 cm (28 3/4 x 4 3/4 x 4 3/4 in.)
        Material
          DescriptionAn extremely large vacuum tube cathode, more than two feet long.

          The entire assembly consists of several components arranged on an axis. Half if it would be housed inside the resnatron, constituting the innermost component of the vacuum tube. Another half would be outside.

          The most visible element is a metal casing with a circular plate on one end, with eight threaded holes for attaching it to the resnatron tube. This casing would be housed inside the resnatron. Inside this casing is a second layer that contains the actual cathode components, and further in is an axle which can be moved in and out to change the geometry of the components inside the resnatron. This axle is in a cavity that would be filled with circulating water.

          Just at the end of the outer casing are the actual cathode filaments, a cage-like element. Further beyond are bellows which extend and contract as the inner axle is moved (and would be filled with water). The assembly ends in a metal disk.

          The section which goes outside the resnatron starts with another circular plate with eight threaded holes. It continues in two metal sections separated by a glass bulb. These have the electrical leads to the cathode, and also have pipes for the cooling systems. At the end is a bellows system and threaded bar that were part of the cathode tuning gear, moving the inner axle in and out.

          A few elements on this end are missing. See RS0081 for a resnatron cathode with the entire tuning drive present.
          Signedectched into disc at center: 63
          Inscribedon label: CATHODE SERIAL #63 / FOR MODEL #2 / RESNATRON TUBE / RRI-28953 IT-10 / BS-31373 -R
          Curatorial RemarksThere are two resnatron cathode assembies in the Collection. RS0080 (missing tuning drive) and RS0081 (complete).
          FunctionThe Resnatron was an extremely large vacuum tube designed at the Radio Research Laboratory, Harvard's secret radar countermeasures facility in World War II. It is a transmitter of microwaves used to disable enemy radars. In particular, it was the microwave source for the gigantic "Tuba" anti-radar system, used to jam the radars from German fighter planes from the ground in England as they pursued allied bombers at night over the Continent.

          This cathode assembly constituted the innermost part of the resnatron. For details on the entire device, refer to instrument RS1235.

          Resnatrons were specifically designed to have easily interchangeable parts, and the cathode assembly can be easily attached and removed from the main tube.

          Historical AttributesThe resnatron was one of the major developments of the Radio Research Laboratory at Harvard University during World War II.
          Resnatron cathode assembly with tuning drive
          Radio Research Laboratory
          Date: 1943-1944
          Object number: RS0081
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