Absorption of X-rays

Principle

The polychromatic X-radiation that is emitted by an X-ray tube is filtered in terms of its energy with the aid of a monocrystal. The resulting monochromatic radiation is used as the primary radiation source for examining the absorption behaviour of various metal foils of different thicknesses.

Tasks

1. Determine the attenuation of the X-radiation by aluminium and zinc foils of different thicknesses and at two different wavelengths of the primary radiation.
2. Determine the mass absorption coefficient μ / ρ for aluminium, zinc and tin absorbers of constant thickness as a function of the wavelength of the primary radiation. Prove the validity of μ /ρ = f (λ3 ) in a graphical manner.
3. Determine the absorption coefficients µ for copper and nickel as a function of the wavelength of the primary radiation. Determine the energy values of the corresponding K shells based on the graphical representation. Prove the validity of μ /ρ = f (λ3 ).

Learning objectives

• Bremsstrahlung
• Characteristic radiation
• Bragg scattering
• Law of absorption
• Mass absorption coefficient
• Absorption edge
• Half value thickness
• Photoelectric effect
• Compton scattering
• Pair production

Supplied with software. Computer not provided.