Basic formalism for X-ray monochromator resolution

The X-ray beam from a synchroton light source like CHESS originates in a small spot of rms typical dimensions of 1-2 mm. The divergence of the beam is of order m/E which is 100 μr for CHESS running at 5.5 GeV. The energy spectrum depends on the beam line. C1 is a bend-magnet end station, so the spectrum is smooth from a few keV up to MeV scales, with an intensity spectrum that drops off at high energy like E^-2.