X rays are produced when fast moving electrons hit a piece of metal (called the target).

Electrons are thermionically emitted by the filament (cathode).

The accelerating voltage is about 100kV.

Less than 1% of the kinetic energy of the electrons is converted into x rays so the anode (target) must be cooled during operation.

X rays cause certain substances to fluoresce, they affect photo-graphic emulsions and can ionise atoms. These three properties can be used to detect x rays.

The intensity of the beam of x rays (Wm^-2) depends on the number of electrons hitting the target per unit time. This depends on the temperature of the filament.

The penetrating power of the beam of x rays depends on the kinetic energy of the electrons. This depends on the accelerating voltage.

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