During the past eight years or so there has been growing interest in using a polarized x-ray source in energy dispersive x-ray fluorescence spectrometers (1,2,3,4). The effect is to annihilate the source x rays before they scatter into the detector, thus significantly increasing the signal to noise ratio.
Both characteristic or Bremsstrahlung radiation can be polarized by 90° scattering from crystals (Bragg angle = 45°) or from amorphous materials respectively. This 90° polarizing scatter event greatly reduces the incident source radiation on a sample. In an effort to regain some intensity use is made of concave surfaces to utilize a manifold of beams (5,6,7).