Bragg deflection

There are three accessories used to produce monochromatic radiation metal foil filters, crystal monochromators, and focusing mirrors. An element with atomic number Z can be used as a selective filter for radiation produced by an element of atomic number Z+ 1. For example, a nickel (Z=28) absorption filter, may be used to cut out the Cu KjS (Z=29 for Cu) radiation, leaving only Cu Ka radiation.Not all white radiation, however, is eliminated by this method. Alternatively a single-crystal monochromator may be used. An intense Bragg reflection from the monochromator crystal is used as the incident beam for X-ray diffraction studies. Focusing mirrors, designed to produce a beam that is not only monochromatic but also convergent, may be used. In this case the incident beam is doubly deflected by two perpendicular mirrors. 

Figure 3.15 Electron deflection by Bragg diffraction of a crystalline specimen (a) image formation in crystalline samples and (b) diffraction at crystal lattice planes and at the contours of inclusions. (Reproduced with permission from M. von Heimandahl, Electron Microscopy of Materials, Academic Press, New York. 1980 Elsevier B. V.)...

Observable diffraction is only obtained when waves deflected from adjacent planes reinforce each other, that is when the path difference ABC in the Hgure is an integer multiple n of the wavelength A of the X-ray radiation used. This leads to Bragg s equation ... 

J. For an irradiation experiment it is necessary to extract a beam of deuterons from an accelerator. The projectile energy is 22 MeV D. For this purpose the beam is deflected and permitted to pass through a thin titanium foil (density 4.5 g cm . Assuming that (Bragg-Kleman rule), what is the... 

The time bandwidth product is a nondimensional parameter defined as the product of the bandwidth 2 A/ and the SAW transit time r. For a Bragg cell not only is size of the absolute deflection important but so is the number of resolvable spots. For a guided wave with a width D the beam divergence angle is... 

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