Flat film camera

A fiber-diffraction pattern is recorded on a flat-film camera in which the fiber-to-photographic film distance is typically in the range of 3 to 4 cm. During exposure to X-rays, the specimen chamber is continuously flushed with a slow and steady stream of helium gas that has been bubbled through a saturated salt solution so that (a) the fiber is maintained at a constant desired r.h. and (b) fogging of the photographic film from air scattering is reduced. 

X-ray diffraction pictures taken with a flat-film camera show that crosslinked SE-BR samples crystallize on stretching. Sharp reflections are observed at an extension ratio of 4 1 (Figure 4). With samples having different degrees of stereoregularity the order for increasing strain-induced crystallization is the same as the order for the rate of low temperature crystallization. 

For wide angle scattering, flat film camera with appropriate film back and intensifying screen (Fig. 21.6)... 

Methods. The wide and small angle x-ray patterns were recorded in a flat film camera at controlled relative humidity using Ni-filtered CuKa radiation generated at 40 kV and 15 mA. 

When monochromatic radiation is used to examine a powder specimen in a Laue (flat-film) camera, the result is often called, for no particularly good reason, a pinhole photograph. (There is no general agreement on the name of this method. Klug and Alexander [G.39], for example, call it the monochromatic-pinhole technique. ) Either a transmission or a back-reflection camera may be used. A typical transmission photograph, made of fine-grained aluminum sheet, is shown in Fig. 6-11. 

Figure 3.1 Diffraction pattern obtained with an isotropic, semicrystalline polymer, poly(3-hydroxybutyrate) by means of a flat film camera. (Courtesy of M. M. Satkowsky.)...

Flat-film cameras are used for all kinds of samples, bulk, fibre, film (foil) and powder specimens. When dealing with structurally anisotropic fibre samples, in particular, one will benefit fi om the use of a cylindrical camera design that will make the diffraction spots (reflections) appear on straight and parallel lines (layer... 

Part of the crystals were allowed to dry and were then inserted into thin wall capillaries for x-ray diffraction studies which were made using a Wahrus flat-film camera mounted on a Siemens Kristalloflex X-ray generator. 

Wide-angle X-ray diffraction (WAXD) analysis of the fibers was carried out with a Philips X-ray generator, Model PW 1729, equipped with a flat film camera. 

Figure 1 X-ray diffraction photographs of poly(y-benzyl L-glutamate)(left) and poly(y-p-chlorobenzyl L-glutamate) (right) taken with the fiber axis normal to the beam. A flat film camera was used.

Lane Camera. This flat-film camera can record both transmission and back-reflection patterns. The principle is illustrated in Figure 14 Figure 15 shows a flat-film pattern. Transmission patterns with polychromatic radiation yield information about the symmetry of a cry.stal (Laue symmetry) or with monochromatic radiation the orientation of the crystallites (preferred orientation, texture) such patterns are recorded, for exitmple. from fibers. Back-reflection patterns permit the nondestructive examination of workpiece.s. 

Texture studies on wires and plates are very important. Initial information can be acquired from transmission and reflection patterns recorded with a flat-film camera (see Fig. 1.5). The type and degree of texture can be determined more or less exactly, depending on the object of investigation and the type of instrument used. One of the best-developed instruments is the Liicke texture goniometer [125]. With this apparatus, the distribution of given net planes can be directly imaged in a pole figure. 

A variant of the Debye-Scherrer is the flat film camera shown in Fig. 6. Here the filtering and pinhole collimation of the X-ray beam are identical to those in a Debye-Scherrer camera, but the pattern is recorded on the flat film. This has the ad-... 

Figure 6. The flat film camera. Normally the entire camera is enclosed in a vacuum chamber or a chamber filled with a gas which causes minimal X-ray scattering, such as helium. Note that because of the smaller size of the beam, smaller reciprocal spacings can be observed.

Experimental Techniques Orientation of the crystalline phase in polyethylene films has been mainly characterized by WAXD [82-98]. In the first studies, the Debye-Scherrer method was employed with a flat-film camera [82-84]. This technique was still used in further work because of its rapidity and its simplicity [87,88,93, 95-98]. 

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