Energy resolution of the X-ray energy detector

Principle

Various metal samples are subjected to polychromatic X-rays. The resulting fluorescence radiation is analysed with the aid of a semiconductor detector and a multichannel analyser. The energy of the characteristic X-ray lines and their full widths at half maximum are determined. In addition, the dependence of the full widths at half maximum and the shift of the line centroid as a function of the counting rate are examined.

Tasks

1. Calibration of the semiconductor detector with the aid of the characteristic radiation of the molybdenum X-ray tube.
2. Recording of the spectra of the fluorescence radiation that is generated by the metal samples.
3. Determination of the energy levels and full widths at half maximum of the characteristic Kα lines and their graphical representation.
4. Determination and graphical representation of the full widths at half maximum as a function of the counting rate, with the Kα line of zircon used as an example.
5. Determination and graphical representation of the shift of the line centroid as a function of the counting rate, with the Kα line of zircon used as an example.

Learning objectives

• Bremsstrahlung
• characteristic X-radiation
• fluorescence radiation
• conduction processes in semiconductors
• doping of semiconductors
• pin-diodes
• resolution and resolving power
• semiconductor energy
• multi-channel analysers