International
Tables for
Crystallography
Volume G
Definition and exchange of crystallographic data
Edited by S. R. Hall and B. McMahon

International Tables for Crystallography (2006). Vol. G. ch. 3.7, pp. 203-204

Section 3.7.4.3. Apparatus and instrumentation at the crystal

H. J. Bernsteina*

a Department of Mathematics and Computer Science, Kramer Science Center, Dowling College, Idle Hour Blvd, Oakdale, NY 11769, USA
Correspondence e-mail: yaya@bernstein-plus-sons.com

3.7.4.3. Apparatus and instrumentation at the crystal

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Data items in these categories are as follows:

(a) DIFFRN_MEASUREMENT [Scheme scheme12]

(b) DIFFRN_MEASUREMENT_AXIS [Scheme scheme13]

The bullet ([\bullet]) indicates a category key. The arrow ([\rightarrow]) is a reference to a parent data item. Items in italics are defined in the mmCIF dictionary.

The DIFFRN_MEASUREMENT category is defined in the mmCIF dictionary (Section 3.6.5.2[link] ; see the detailed discussion in Section 3.2.2.2.3[link] ). The CBF/imgCIF dictionary restates the DIFFRN_MEASUREMENT category, adding new tags. Data items in the DIFFRN_MEASUREMENT category record details about the device used to orient and/or position the crystal during data measurement and the manner in which the diffraction data were measured. To allow for multiple measurement devices, _diffrn_measurement.id has been added to the category key. The number of axes is given by the value of _diffrn_measurement.number_of_axes. The axes should be described using entries in DIFFRN_MEASUREMENT_AXIS.

Data items in the DIFFRN_MEASUREMENT_AXIS category associate axes with goniometers, just as data items in the DIFFRN_DETECTOR_AXIS category associate axes with detectors.








































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