X-ray has a wavelength of approx. 0.01 to 10 nm.
Coolidge X-ray tube
X-rays are emitted from the hot cathode(-ve) and accelerated through a potential difference V of several thousand volts.(e.g. 50kV) The high-energy electrons strike a target embedded in a copper anode (+ve).
Choice of material for anode:
- Most electrons hit the metal target but only cause vibration of atoms. As a result, the metal gains a high amount of energy and will get heated. Thus, a metal of high melting point is necessary
- High atomic number so that more X-ray are produced
- Good conductor of heat
Choice of material for cathode:
- Low Work Function
- Low heat capacity