The Borrmann effect (or Borrmann–Campbell effect after
Gerhard Borrmann
Gerhard Borrmann (30 April 1908 – 12 April 2006) was a German physicist.
He was born in Diedenhofen, then part of Germany, and received his early education there. He continued his secondary school at Gießen, where he apprenticed at a steel ...
and Herbert N. Campbell) is the anomalous increase in the intensity of X-rays transmitted through a crystal when it is being set up for
Bragg reflection
In physics and chemistry , Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave ...
.
The Borrmann effect—a dramatic increase in transparency to X-ray beams—is observed when X-rays satisfying
Bragg's law
In physics and chemistry , Bragg's law, Wulff–Bragg's condition or Laue–Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice. It encompasses the superposition of wave ...
diffract through a perfect crystal. The minimization of absorption seen in the Borrmann effect has been explained by noting that the electric field of the X-ray beam approaches zero amplitude at the crystal planes, thus avoiding the atoms.
References
*
*{{cite journal , last1=Pettifer , first1=Robert F. , first2=Stephen P. , last2=Collins , first3=David , last3=Laundy , year=2009 , title=Quadrupole transitions revealed by Borrmann spectroscopy , journal=
Nature
Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
, volume=454 , issue=7201 , pages=196–199 , doi=10.1038/nature07099 , bibcode=2008Natur.454..196P , pmid=18615080, s2cid=4346649
* Borrmann, Gerhard; ''Über Extinktionsdiagramme von Quarz'', Physikalische Zeitschrift 42, 157–162 (1941)
''Die Absorption von Röntgenstrahlen im Fall der Interferenz'', Zeitschrift für Physik 127, 297–323 (1950)- original articles on Borrmann effect
* Campbell, Herbert N.
''X‐Ray Absorption in a Crystal Set at the Bragg Angle'' Journal of Applied Physics 22, 1139 (1951)
*
von Laue, Max''Die Absorption der Röntgenstrahlen in Kristallen im Interferenzfall'', Acta Crystallographica 2, 106–113 (1949)- original explanation of Borrmann effect
X-ray crystallography