DRAFT DICTIONARY CBF/imgCIF Extensions Dictionary | Draft version 1.5 for comment

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Index

##### Image dictionary (imgCIF) version 1.5.4

# _diffrn_radiation.div_x_y_source

Name:
`'_diffrn_radiation.div_x_y_source'`

Definition:

            Beam crossfire correlation degrees^2^ between the
                   crossfire laboratory X-axis component and the crossfire
                   laboratory Y-axis component (see AXIS category).

                   This is a characteristic of the X-ray beam as it illuminates
                   the sample (or specimen) after all monochromation and
                   collimation.

                   This is the mean of the products of the deviations of the
                   direction of each photon in XZ plane times the deviations
                   of the direction of the same photon in the YZ plane
                   around the mean source beam direction.  This will be zero
                   for uncorrelated crossfire.

                   Note that some synchrotrons, this value is specified in
                   milliradians^2^, in which case a conversion would be needed.
                   To go from a value in milliradians^2^ to a value in
                   degrees^2^, multiply by 0.180^2^ and divide by \p^2^.

Type: float

Mandatory item: no

Enumeration default: 0.0

Category: diffrn_radiation

#### HTML version of draft dictionary created by modified version of makedicthtml by B. McMahon from modified version of imgCIF dcitionary 1.3.2 which is subject to the following copyright:

Copyright © 2005 International Union of Crystallography