One primary and two secondary slits are located in the Optic hutch.optics_hutch_schema.jpg

Primary slits delimits white beam to 4 mm by 4 mm size to protect monochromator mecanics while using the maximal possible beam size to be exploited by optics (monochromator and mirror).

Secondary slits 1 and 2 clean up the beam after monochromator and mirror from any parasitic scattering.

They can be moved via spec OH etheir blade by blade (ex. mvr psf 1 to move primary slit front blade by 1 mm in positive direction) or by two together (ex. mv ss2vg 2 will put verticall gap of second secondary slit to 2 mm).