Guinier range

In the Guinier range of q (qRgchain length is introduced one obtains ... 

Information about both the size and the geometry of the scattering particles can be obtained from different scattering domains. In the Guinier range with QR < < 1 the scattering function can be written... 

Guinier range 2 Intermediate range 3 Asymptotic range, o values measured at a wavelength 436 nm values measured at a wavelength 546 nm. 

In the Guinier range, irrespeetive of the particles shape, the intensity always reduces to... 

Figure 4 Kratky plot, (a) Guinier range. The arrow indicates the intersection between die two asynqitotic regimes Gaussian coil (b) and rod (c).

At low values of Q, in the Guinier range, the form factor reduces to... 

The structure factor of the model short range order regions and the experimental WAXS pattern are shown in Fig. 21. The strong Guinier scattering at... 

Regourd and Guinier (Rl) reported unit cell parameters for the ferrite phase in five clinkers. The ranges observed were a = 0.5517-0.5555 nm, h = 1.455-1.462 nm, c = 0.5335-0.5350 nm. Boikova (B4) reported XRD powder spacings for clinker ferrites which indicate similar values. The similarity of these cell parameters to those of the laboratory preparations... 

On the debit side, the Seemann-Bohlin camera has the disadvantage that the lines registered on the film cover only a limited range of 26 values, particularly on the low-angle side. The Seemann-Bohlin camera, in itself, is now virtually obsolete (the diffractometer has greater resolution), except in combination with a monochromator. The combination is then called a Guinier camera (Sec. 6-14). 

Fig. 6-17 Single film with four powder patterns, made with Guinier-de WolflF camera. The two bottom patterns are of quartz, the third from the bottom is of ammonium alum, and the top one is of a mixture of quartz and ammonium alum. The range of 10 angles is 4° to 82°. (Courtesy of Enraf-Nonius Inc., Delft.)...

Compared to a Debye-Scherrer camera of the same size, operated directly from the x-ray tube, a Guinier camera provides a much clearer pattern with twice the resolution and about the same exposure time, but any one Guinier camera covers only a limited range of 10. It is best suited to the examination of particular parts of complex patterns. 

Guinier and Fournet (1955) determined that for an ensemble of randomly oriented, identical scattering particles in which there is no long-range order the scattered intensity, IQi), may be represented to a close approximation by the equation... 

Standard techniques have been used to analyze the SAXS profiles (16). A Guinier analysis of the low q portion of the curves could not be utilized since a plot of In I(q) against q2 was not linear over the q-range investigated. This would have given an estimate of the size of the entities giving rise to the zero-order scattering. 

---