Slit Desmearing

For the case of isotropic scattering recorded with slit-focus cameras there are several desmearing options. If the slit may be considered infinite, the observed scattering intensity is... 

If the slit length is finite and the scattering intensity shall be desmeared, the profile W (si, S3) of the primary beam must be known. In order to carry out the desmear-ing numerically, different algorithms have been proposed, but few of these methods are able to manage the derivative problem from Eq. (4.6) properly for noisy data. One of them is the method developed by Glatter [68],... 

Small angle X-ray scattering (SAXS) was measured with a Kratky camera using nickel filtered CuKa radiation. The width of the entrance and detector slits were 20 and 50 pm, respectively. No desmearing procedure was applied to the scattering curves. Absolute measurements were carried out by using a Lupolen standard. 

Fig. 12. Desmearing of J (m)(see Figs. 10,11 and Eq. (30) includes smearing by slit length and slit width) Crosses ii(m) empty circles J (m)(effect of slight width has been removed cf. Eq.(33)),filled circles desmeared intensities I(q)...

X-ray beam is rectangular, which occurs when slits are used to collimate the beam, the resulting pattern will show smearing of intensity due to the incident beam shape. Ibese effects must be removed by mathematically "desmearing" the pattern to obtain the corrected intensity. The topic of desmearing is extensively covered in the references (3-5). Least distortion of the measured intensity occurs when pinhole collimation is used. 

Figure 8.26 gives desmeared SAXS profiles with values of q that were obtained using slit collimation and a one-dimensional (ID) position sensitive detector, where q = (47T/k)sin(0/2) is the magnitude of scattering vector q, with k and 6 being the... 

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