Figure 1
Set-up scheme for the thermal deformation profile measurements using rocking angle scans at various vertical positions of a narrow-gap exit slit. The rocking angle [theta]' corresponding to the peak intensity in the rocking curve for the distorted first crystal is slightly different from the Bragg angle [theta]B (peak position for the undistorted crystal). The distortion of the crystal in terms of angle is given by [Delta][theta] = [theta]' - [theta]B. Each slit position xs (xs = 0 for the centre of the beam) allows the rocking curve to be recorded relative to the X-ray beam impinging on the first crystal surface at the position xc = xs/sin[theta]B. The thermal slope distribution [Delta][theta](xc) of the crystal can be measured by varying the vertical positions of a narrow-gap slit after the monochromator.  [article HTML]