Machlett “CYR” Tube

















(E.R.N.Grigg - Trail of the Invisible Light - Charles C. Thomas, 1965 - p.82)



             The tube proper is about 31cms long, excluding the radiator. The black metal housing is 26.5cms long, 9cms in diameter and about 6mms thick, with an additional internal lead lining of 2mms.

             The cathode end of the housing is snugly closed, with a protruding Edison screw-type filament connection, while the anode end is about a 1cm thick ceramic disc fitted with six 1cm aeration holes, symmetrically placed around a circular opening through which passes the anode shaft.

             A nine-layer black-painted copper heat radiator is screwed on this protruding anode shaft and connects directly to the high voltage line.

             The tube is of the line focus (Goetze) type, with a low target angle, and a projected focal spot estimated at about a 3mm square. The round radiation window is fitted with a removable aluminium filter 0.5 mm thick. No other specifications are available.


             Click HERE to read the CYR story from the Machlett Cathode Press Memorial Issue”, 1955.


This particular tube is known to have been in use in the late thirties

in the x-ray department of the American University Hospital in Beirut.

It was graciously donated to this collection by the late Mr. Munir Moujahes, RT

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