International
Tables for Crystallography Volume C Mathematical, physical and chemical tables Edited by E. Prince © International Union of Crystallography 2006 
International Tables for Crystallography (2006). Vol. C, ch. 6.4, p. 612

From the definition of the extinction factor, the integrated intensity from a nonabsorbing crystal in which the block size is sufficiently small, and the mosaic spread is sufficiently large, will approach the kinematic limit. It is instructive to examine the behaviour in the limit of large block size and low mosaic spread. The volume of the mosaic block is v and the volume of the crystal is V. The number of blocks in the crystal is . The surface area of the block is and of the crystal is . The subscripts L and B will again be used for the Laue and the Bragg case, respectively. The kinematic integrated intensity is given by
For this condition, the limiting values of the integrated intensity are , and In this limit, which was also noted by Bacon & Lowde (1948) and by Hamilton (1957), the intensity is proportional only to the mosaic spread and to the surface area of the crystal. No structural information is obtained from the experiment.
Only the Bragg case for thick crystals will be considered here. The asymptotic values of A, B, and C are , , and , respectively, so that For BCx small, the integrated intensity, , is given by For BCx large, It can be shown that the parameter g (which has no relation to the parameter g used to describe the mosaicblock distribution) used by Zachariasen (1945) in discussing this case is equal to −μ/2NCF. Hence, on his y scale, The value he obtained is I_{B} = 8/3[1 − 2g], while Sabine & Blair (1992) found I_{B} = 8/3[1 − 2.36g].
References
Bacon, G. E. & Lowde, R. D. (1948). Secondary extinction and neutron crystallography. Acta Cryst. 1, 303–314.Hamilton, W. C. (1957). The effect of crystal shape and setting on secondary extinction. Acta Cryst. 10, 629–634.
Sabine, T. M. & Blair, D. G. (1992). The Ewald and Darwin limits obtained from the Hamilton–Darwin energy transfer equations. Acta Cryst. A48, 98–103.
Zachariasen, W. H. (1945). Theory of Xray diffraction in crystals. New York: John Wiley, Dover.