Specifications

Beamline optical scheme

Collimation mirror

The x-ray beam produced in the bending magnet passes through a set of double slits defining an aperture of about 1.4 x 1.4 mm².

The divergent beam passing through the slits is then collimated by a Rh-coated, spherical profile mirror. The vertically collimated beam reflected off the collimator proceeds towards the monochromator. 

Monochromator

The monochromator was designed internally at Elettra Sincrotrone Trieste by the X-Ray Fluorescence team.
It operates in the energy range 2 - 14 keV with small spectral bandwidth (Si(111), InSb crystals) or in the 0.7 - 14 keV with high flux (multilayers). 

The crystals and multilayers are mounted on a support (shown in the picture and scheme above) which is moved according to the energy range needed for each experiment. Moving the support from left to right, one accesses the Si (111), InSb(111), double multilayer for high and medium energies, and low energies multilayer.
 

Refocusing mirror

The refocusing mirror, placed in close vicinity of the monochromator, is a Rh-coated, toroidal mirror with af bicycle tyre profile. It focuses the beam both vertically and horizontally at the exit slits.

Higher Order Suppressor

While energies above 15 keV are absorbed upon reflection on the Rh-coated mirrors, a higher order harmonics contamination exists in the monochromatised beam up to about 7 keV. 

The suppression of such higher order radiation is ensured by an independent optical device named the Higher Order Suppressor (HOS). The HOS is made up of a pair of parallel plane mirrors intercepting the beam in grazing incidence.

The mirror has two sides having different coatings: 

A Rhodium coating, for energies between 8 and 14 keV, operated at fixed angle, provides 85% of transmission.

A Carbon coating for photon energies < 8 keV,  operated with a variable angle, provides a transmission of about 95% between 3.5 and 8 keV, and of about 50% at 0.7 keV.