Click to open a full view of the tomographTomograph pictureTomograph picture 

The microtomography setup was implemented on the multi-purpose platform (MPP) in fall of 2003. It was designed to meet requirements of medium resolution x-ray microtomography (pixel size 5.3 and 7.5 µm) with the possibility of extension to higher spatial resolutions (pixel size 0.7, 1.4 and 1.7 µm). For medium resolution experiments the Si(111) double-crystal monochromator can be employed, however,  to circumvent the flux issue for higher resolutions the use of the double multilayer monochromator is mandatory.                

The setup consists of a dedicated sample stage mounted on the 1st axis of the MPP at a distance of 39.3 m from the source and a 2D CCD based detector, namely the FReLoN camera, placed behind on the either the 2nd or 3rd axis. The sample stage comprises essentially an in-house designed vertical high-precision Z-stage for specimen height adjustment on which the Newport rotary and linear stages are mounted. In addition two Micos micropositioners control the horizontal transverse to the x-ray beam translations of the sample placed at a height of typically 72 mm from the platform. For alignment purposes of the microtomograph (to optimise the orthogonality between the rotation axis, the x-ray beam and the rows of the camera pixels) the whole Z-stage has an integrated tilt and the FReLoN camera head is mounted on rotation stage (resolution 0.9 mdeg).

The high velocity (200 deg/s maximum) Newport rotary PM500-360 stage has a resolution of 0.3 mdeg, an absolute accurarcy of 6 mdeg with bi-directional repeatability of 0.6 mdeg and a total runout error of 9 µrad. The Newport linear stage has 100 mm of travel, resolution of 0.1 µm and an absolute accuracy of ±0.5 µm. To assure the sample vertical translation and adjustment of the microtomograph for different incident x-ray beam heights in the range of 45 mm the Z-stage stroke is 100 mm with a resolution ~0.1 µm.

The BM5 FReLoN (2Kx2K) camera developed at the ESRF, is a fast-readout, low-noise Multi-Pinned Phase detector with a 14 bit resolution CCD having 2048x2048 pixels and a pixel size of 14 µm2. With the available optics the spacial resolition range obtained is from 1.4 to 15 µm. Optics using a 13.93 µm thick LAG:Tb (YAG 170 µm substrate) scintillator gives pixel sizes of 0.7, 1.4, 1.7 µm and field of views of 1.4 mm2, 2.8 mm2 and 3.4 mm2, respectively. The 5.3 µm input pixel size optics is equipped with a 5 µm thick Phosphor P43 (Gd2O2S:Tb) with a grain size of 1 µm and gives a field of view of 10.85 mm2.  For 7.5 µm input pixel size and 15.3 mm2 field of view, the optics are equipped with a 10 µm thick Gd2O2S:Tb scintillator screen. The camera is shielded by means of a brass housing 2 mm thick. The FReLoN camera is coupled to either the 2nd or 3rd axis towers to permit motion in x and y direction and it can be translated vertically. The sample to detector distance can be varied from 0 up to 1.5 m with a step increment of 1 µm giving the possibility to perform phase-contrast microtomography.