The monochromator is a pseudo channel-cut type based on a double crystal scheme (DCM)  with two fixed Si(111) crystals moved together by a simple goniometer circle, in the (-n,+n) configuration. The first crystal, with dimension of ~120 mm x 80 mm x 60 mm (L x W x P), is fixed to the rotation table. The second crystal is fixed to a crystal cage with four independent movements (Three tilts –pitch, roll and yaw- and one translation to adapt the gap between the crystals) and has a dimension of ~130 mm x 80 mm (L x W).  The operating energy range is from 5 keV to 40 keV with an energy intrinsic resolution of  ~1.4 x 10-4. The Vacuum chamber is supported by a huge granite block, which incorporates high precision actuators for the monochromator alignment respect to the incident beam. The monochromator is located at 31.8 meters from the source. The first monochromator crystal is cooled by means of a LN2 cryo-cooler pump.