The fluorescence measurements are performed using a three-element SDD (RaySpec, UK) placed perpendicular to the incoming beam. The three crystals of 50 mm² active area and 450 µm thickness each are arranged vertically along an arc with a 28 mm radius. The energy resolution is 131 eV (@MnKa). All three elements have 12.5 µm DuraBe-plus window. A long or short collimator can be used optionally, with optimum sample-detector distance of 34 mm and 14.6 mm, respectively, from the central sensor. The collimator is made of high purity (>99%) Ta, Cr, Ti, and Al.

The detector system is water cooled. The SDD output signal of each element is processed individually by a four-channel Digital Signal Processing unit (DXP-XMAP, XIA LLC, USA).
The positioning of the detector-sample distance is performed using one motorized linear stage, connected to the SMC for the 7-axis manipulator and the base system. 

 

 

Another detector (XFlash 5030, Bruker Nano GmbH, Germany) is also installed on the vacuum chamber, at 135deg from the incoming beam. This SDD has a 30 mm² nominal crystal area, a thickness of 450 µm and resolution equal to 131 eV (@MnKa). It is equipped with a Super Light Element Window (SLEW) of the type AP 3.3. A Zr collimator is placed in front of the detector chip to prevent the detection of photons at the edges of the crystal and to improve the energy resolution and the peak to background ratio. The presence of the collimator limits the effective active area to about 25 mm². When the optimum detection of light elements (Z<14) is not necessary, the electron trap can be replaced by a 8.5 µm Be window.

The SDD output signal is processed by a Digital Signal Processing unit (by Bruker Nano GmbH) providing detector bias supply, pile up rejection, input/output rate meter, dead time correction using an internal “zero” peak and selectable shaping time constants in the range (0.89 – 6.1 µs). For more details see the User’s Manual of the IAEA control software.