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Image dictionary (imgCIF) version 1.3.2




   The angle in degrees, as viewed from the specimen, between
   the normal to the polarization plane and the laboratory Y
   axis as defined in the AXIS category.

   Note that this is the angle of polarization of the source
   photons, either directly from a synchrotron beamline or
   from a monchromator.

   This differs from the value of
   in that _diffrn_radiation.polarisn_norm refers to
   polarization relative to the diffraction plane rather than
   to the laboratory axis system.

   In the case of an unpolarized beam, or a beam with true
   circular polarization, in which no single plane of
   polarization can be determined, the plane should be taken
   as the XZ plane and the angle as 0.

   See _diffrn_radiation.polarizn_source_ratio.

Type: float

Mandatory item: no

The permitted range is [-90.0, 90.0]

Enumeration default: 0.0

Category: diffrn_radiation