View source for Brilliance

<font color="blue">Brillance</font> (''Fr'').


In contrast to [[brightness]], '''brilliance''' additionally takes the beam dimensions into account and is defined as brightness per mm<sup>2</sup>. The unit is p.p.s. <math>\times</math>mm<sup>2</sup> <math>\times</math>mrad<sup>2</sup>. Brilliance is maximized by making the beam size and divergence as small as possible, and the photon flux as large as possible. Two X-ray beams may have the same flux density but different brilliance if the two beams have different beam divergence. Brilliance is thus an appropriate parameter to use when comparing two X-ray sources with different focal spot sizes.