Vertical divergence

Fig. 4. Experimental arrangement on the XAS instrument 8.1 at the SRS, where a slitless monochromator is used and the crystals are mechanically bent to account for the vertical divergence (0.2 mrad) of the x-rays from the source. A toroidal mirror is placed after the monochromator, which provides the focussing...

Vertical divergence error—may be decreased by decreasing the vertical opening of the detector slit. 

Note that the resolution in the vertical plane is higher due to the smaller vertical divergence. A typical calculation of the vertical resolution for a camera shown in Fig. 23 is depicted in Fig. 28. The following parameters were used ... 

A considerably higher resolution is expected for a small angle scattering camera at a dedicated source like the NSLS at Brookhaven or the projected ESRF which is due to a smaller source point, a smaller vertical divergence and an optimum location of the optical elements. 

Vertical divergence of the incident beam. This error is minimized, with loss of intensity, by decreasing the vertical opening of the counter slit. 

The vertical divergence is limited by two series of shts placed before and after the sample. These slits, referred to as Soller slits [SOL 24], are corrtprised of parallel plates, regularly spaced out, that divide the beam into several, very slightly divergent beams. 

Figure 2.6 Angular distribution of the radiation emitted by an electron circulating at a speed close to the speed of light. The radiation emerges tangential to the electron orbit, and the vertical divergence of the radiation is very small and is inversely proportional to the energy E of the circulating electron.

The use of an organic monochromator made the reflected beam practically nondivergent in the horizontal plane. The vertical divergence was 2° when two 4-mm-high entry slits were used. The focusing arrangement was such that the counter slit, the center of the surface of the sample, and the center of the surface of the monochromator crystal (acting as the source of rays) were located on the same circle. 

Mo-W alloy anode) or a rotating anode tube. The beam is shaped like a strip of paper by means of precisely aligned slits its vertical divergence is adjusted to less than 0.01°. 

Collimator Series of flat, high X-ray absorbing metal plates, used to limit the vertical divergence of a beam of X rays. 

---