J J Thomson and his student Ernest Rutherford were the first to demonstrate the ionization of air by X rays. Thomson himself is best known for deflecting cathode rays [1897] with a perpendicular electric field - showing that they were negative particles! He measured the speed of the particles and the charge to mass ratio. The laboratory made their own tubes and power supplies. It was ground-breaking work.

Diagram of Thomson's tube

The electron was the first subatomic particle to be identified.

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