Compton effect - energy-dispersive direct measurement

Principle

Photons of the molybdenum Kα X-ray line are scattered at the quasi-free electrons of an acrylic glass cuboid. The energy of the scattered photons is determined in an angle-dependent manner with the aid of a swivelling semiconductor detector and a multi-channel analyser.

Tasks

1. Energy calibration of the multi-channel analyser with the aid of the two characteristic molybdenum X-ray lines Kα and Kβ.
2. Energy determination of the photons of the Mo-Kα-line that are scattered through an acrylic glass element as a function of the scattering angle.
3. Comparison of the measured energy values of the lines of scatter with the calculated energy values.
4. Calculation of the Compton wavelength of electrons and a comparison of this value with the corresponding value of the 90° scattering.

Learning objectives

• Bremsstrahlung
• Characteristic X-radiation
• Compton scattering
• Compton wavelength
• Conservation of energy and momentum
• Rest mass and rest energy of the electron
• Relativistic electron mass and energy
• Semiconductor detector
• Multichannel analyser