Principle

Fluorescence radiation of the elements of a sample can cause fluorescence radiation inside the detector and its housing if the energy is sufficiently high. As a result, the spectrum may include lines that are not caused by the sample. For the detection of potential additional lines, the detector is subjected to monochromatic X-radiation with the aid of a monocrystal. For comparison, the fluorescence spectra of pure metal samples are measured.

Tasks

1. Calibrate the semiconductor energy detector with the aid of the characteristic fluorescence radiation of the calibration sample.
2. Irradiate the X-ray energy detector with monoenergetic X-rays that are produced by the Bragg reflection on an LiF monocrystal. Measure the resulting fluorescence spectrum.
3. Determine of the energy of the spectrum lines.
4. Assign the lines to elements by comparing the measured values with table values.
5. Comparative measurement and evaluation of the fluorescence spectra of pure metal samples.

Learning objectives

• Bremsstrahlung
• Characteristic X-radiation
• Fluorescence radiation
• Fluorescent yield
• Interference of X-rays
• Crystal structures
• Bragg's law
• Compton scattering
• Escape peaks
• Semiconductor energy detectors
• Multichannel analysers