Figure 2
Background-corrected images were taken with a Gadox scintillator fibre-optically coupled CMOS sensor using two different apertures. As source only the U32 undulator is used which is set to a gap of 18 mm. White beam slits were set at 0.5 mm × 0.5 mm. (a) White beam image as collected using two 50 µm foils stacked on top of each other, one with a 400 µm-diameter pinhole and one with a 25 µm pinhole (indicated by red box; the two apertures are not perfectly aligned with respect with each other). The area to the right of the red dashed curve is not exposed due to the shadow of the thick copper window mount. (b) White beam image as collected using a single 70 µm aperture in a 1 mm-thick Pb foil. Throughout the sensor was oriented in such a way that the horizontal position of the beam was aligned with the vertical position on the sensor and vice versa. Note that the scintillator screen has some scratches and imperfections. The red dashed circled area indicates a feature that is probably due to diffraction from the CVD diamond material. (c) Beam profiles (top frame: horizontal beam profile; bottom frame: vertical beam profile) calculated by summing pixel intensities row- and column-wise each for the image in (b) with their respective Gaussian best fits. |