Lang method

There are many methods of X-ray topography, though the most popitlar are the Lang method with slit-collimated radiation and the double-crystal methods, which may be thought of as high resolution diffractometry with an imaging... 

Lang method The Lang factor for a fluid processing unit starting with purchased equipment costs is 5.0. Therefore, fixed capital investment is 2,820,000 X 5.0 X 1.035 X 1.040 = 15,177,000. 

Experience has shown that the fixed capital investment by the Lang method is generally higher than that of the other methods. Whatever figure is reported to management, it is advisable to state the potential accuracy of these methods. 

Fig. 8-34 Lang method. Slits Si and S2 are fixed. The crystal and the photographic plate are mounted on a stage that can be slowly traversed in the directions shown.

The Lang method can also reveal magnetic domains in ferromagnetic and ferrimagnetic materials [8.21]. Here, spontaneous magnetostrictive strains in domains and domain walls are enough to upset the regularity of the lattice and constitute crystal imperfections. 

SCpQ is the sum of the delivered costs of all the major items of process equipment. The major advantage of the Lang method is that the cost of equipment is available. 

I would like to know whether the Holland-lang method makes use of different boundary conditions compared to the Holland method, as it was published In 1959. Are there any other differences ... 

Another method of X-ray diffraetion topography is the Lang method, where a ribbon X-ray beam is eollimated to such a small angular divergence that only one characteristic wavelength is diffracted by the crystal. Simultaneous movement of the crystal and film allow a large area of the crystal to be investigated. 

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