7 Quantum Physics
7.12 Duane-Hunt displacement law
P2540901
Duane-Hunt displacement law and Planck's "quantum of action"
Bremsspectrum of copper for three different anode voltages U (15 kV, 15 kV, and 31 kV), x-axis:
glancing angle ? /°
Principle
X-ray spectra are recorded as a function of the anode voltage.
The short wavelength limit of the "Bremsspectrum" is used to
determine the agreement with the Duane-Hunt displacement law,
and to determine Planck's "quantum of action".
Tasks
1. Record the intensity of the X-rays emitted by the copper anode at various anode voltages as a function of the Bragg
angle using an LiF monocrystal.
2. Determine the short wavelength limit (= maximum energy)
of the bremsspectrum for the spectra obtained in (1).
3. Use the results to verify the Duane-Hunt displacement law,
and to determine Planck's "quantum of action".
What you can learn about
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X-ray tube
Bremsstrahlung
Characteristic X-ray radiation
Energy levels
Crystal structures
Lattice constant
Interference
The Bragg equation
Main articles
XR 4.0 expert unit
XR 4.0 X-ray goniometer
XR 4.0 X-ray Plug-in Cu tube
XR 4.0 Software measure X-ray
Geiger-Mueller Counter tube, type B
XR 4.0 X-ray Lithium fluoride crystal,
mounted
XR 4.0 X-ray Diaphragm tube d = 2 mm
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excellence in science
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Max Planck
1918, Nobel Prize in Physics