Energy-dispersive measurements of K- and L-absorption edges

Principle

Thin powder samples are subjected to polychromatic X-rays. The energy of the radiation that passes through the samples is analysed with the aid of a semiconductor detector and a multi-channel analyser. The energy of the corresponding absorption edges is determined and the resulting Moseley diagrams are used to determine the Rydberg frequency, the screening constant and the principal quantum numbers.

Tasks

1. Calibration of the semiconductor energy detector with the aid of the characteristic radiation of the calibration sample.
2. Recording of the energy spectra of the polychromatic X-rays that pass through the powder samples.
3. Determination of the energy of the corresponding K- and L-absorption edges.
4. Determination of the Rydberg frequency, screening constants, and principal quantum numbers with the aid of the resulting Moseley diagrams.

Learning objectives

• Bremsstrahlung
• Characteristic X-radiation
• Absorption of X-rays
• Bohr's atom model
• Energy levels
• Moseley's law
• Rydberg frequency
• Screening constant
• Semiconductor energydetectors
• Multichannel analysers
  

Software included. Computer not provided.