Tellurite And Fluorotellurite Glasses For Active And Passive

5. Crystallisation studies; MDO 137
Fig. (5.2): Diffraction of incident X-rays from parallel rows of atoms in a crystalline
lattice (see text for definitions of terms) [1].
Consider two sets of planes A and B, with interplanar spacing d. If a wavefront of in-
phase X-rays, p1p2p3, is incident on these planes with an angle θi, this gives rise to
‘reflected’ beams c1, c2 and c3 with an angle of θr. The rays p1E1c1 and p2E2c2 should
arrive at the same time at c1c2c3 only if they are in phase. This means the path difference
between p1E1c1 and p2E2c2 should be given by equation (5.1).
n λ = ME + NE
(5.1)
2
2
If we consider the two right angle triangles, E1ME2 and E1NE2, shown in fig. (5.2b):
Therefore:
E2M
E2M
sin θ i = =
(5.2)
E E d
2
1