Before revision: The magic angle is a particular value of the collection-angle of an electron microscope at which the measured energy-loss spectrum "magically" becomes independent of the tilt-angle of the sample with respect to the beam direction.
After revision: The magic angle is a particular value of the collection angle of an electron microscope at which the measured energy-loss spectrum "magically" becomes independent of the tilt angle of the sample with respect to the beam direction.