A post-monochromator is installed in tandem with the main monochromator in order to further improve monochromatic the X-ray beam resolution. High-resolution is mandatory for high resolution experiments (for instance high resolution HAXPES measurements). High stability and precision are guaranteed, since the system is mounted/supported on a huge granit block. The Post-monochromator is  identical to the main monochromator, a pseudo channel-cut type based on a double crystal scheme (DCM)  with two fixed Si(311) 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. Both crystalls are keep a room temperature since the absence of cooling and the use of (311) silicon crystals. Such a configuration provides an intrisic energy resolution of 2.6x10-5. Hence, a beam bandwidth of 400 meV at a photon energy of 15 keV is  achieved. The photon bandwidth at 5 keV is further reduced to 80 meV.  Later and depending of the beamline performance in term of brilliance high Miller indices Si crystal could be installed in order to improve even more the beamline resolution.