Borrmann effect
From Online Dictionary of Crystallography
(Redirected from Anomalous transmission)
Effet Borrmann (Fr). Borrmann Effekt (Ge). Effetto Borrmann (It). ボルマン効果 (Ja). Бормана эффект (Ru). Efecto Borrmann (Sp).
Definition
Due to anomalous absorption, type 1 wavefields propagate in a perfect or nearly perfect crystal with a less than normal absorption. For details and the physical interpretation, see anomalous absorption.
Super-Borrmann effect
It is the enhancement of the Borrmann effect in a three-beam case, e.g. when the [math]111 [/math] and [math]{\bar 1}11 [/math] reflections are simultaneously excited in a silicon or germanium crystal.
History
The Borrmann effect was first discovered in quartz [Borrmann, G. (1941). Physik Z., 42, 157-162. Über Extinktionsdiagramme der Röntgenstrahlen von Quarz] and then in calcite crystals [Borrmann, G. (1950). Z. Phys. 127, 297-323. Die Absorption von Röntgenstrahlen in Fall der Interferenz], and interpreted by Laue [Laue, M. von (1949). Acta Cryst. 2, 106-113. Die Absorption der Röntgenstrahlen in Kristallen im Interferenzfall] .
The super-Borrmann effect was first observed by Borrmann, G. and Hartwig, W. [(1965). Z. Krist. 121, 401-409. Die Absorption der Röntgenstrahlen im Dreistrahlfall der Interferenz].
See also
- Chapter 5.1 of International Tables for Crystallography, Volume B for X-rays
- Chapter 5.2 of International Tables for Crystallography, Volume B for electrons
- Chapter 5.3 of International Tables for Crystallography, Volume B for neutrons