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X-ray Absorption and Fluorescence

LEVEL 3 LABORATORY

High Energy Physics

X-Ray Absorption and Fluorescence


Objectives of the Project

  • Measure the mass absorption coefficient of x-rays for a number of different metals.
  • Investigate the energy and Z dependence of the photoelectric absorption cross-section.
  • Observe the fluorescence spectra of the same set of metal samples.
  • Investigate the fluorescence spectra of a variety of materials.

Apparatus

  • Amptek Mini-X x-ray source
  • Solid state Amptek X-123 x-ray detector assembly.

Experimental Procedure

  1. The Mini-X x-ray source has a silver target and produces characteristic x-rays in a range from 0 to 50 keV.
  2. Set the amplification range of the detector so that the entire x-ray spectrum is recorded at a voltage of 50 kV.
  3. Record the spectra at various volatge settings of the Mini-X.
  4. Measure the background count rate of the Amptek-123 detector.
  5. Measure the absorption coefficients of Al, Cu, Sn and Fe (Stainless steel).
  6. Interpret the results in terms of energy and atomic number dependence.
  7. Repeat the measurements with the fluorescence set-up.
  8. Investigate other materials with the fluorescence set-up to determine their compositions e.g. alloys, ceramics, soil samples.

Safety and Precautions

The Mini-X source emits high intensity x-rays and can only be used safely when it is contained within an interlocked shielded box.

References

  • Knoll, G.F.: “Radiation Detection and Measurement”,
  • Kaye, G.W.C. and Laby, T.H.: Tables of Physical and Chemical Constants (X-rays).
  • Useful statistics


External links