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

International Tables for Crystallography (2006). Vol. G, ch. 5.6, pp. 551-552

Section Detector geometry functions

P. J. Ellisa and H. J. Bernsteinb*

aStanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, CA 94025, USA, and bDepartment of Mathematics and Computer Science, Kramer Science Center, Dowling College, Idle Hour Blvd, Oakdale, NY 11769, USA
Correspondence e-mail: Detector geometry functions

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In a similar manner, a CBF/imgCIF file includes a description of the surface of each detector and the arrangement of the pixels in space. CBFlib provides eight functions for analysing this description: [Scheme scheme125] cbf_construct_detector uses data from the categories DIFFRN, DIFFRN_DETECTOR, DIFFRN_DETECTOR_ELEMENT, DIFFRN_DETECTOR_AXIS, AXIS, ARRAY_STRUCTURE_LIST and ARRAY_STRUCTURE_LIST_AXIS to construct a geometric representation of detector element element_number and initializes the cbf_detector handle, detector. cbf_free_detector frees the detector structure; cbf_get_beam_center calculates the location at which the beam intersects the detector surface, either in terms of the pixel indices (index1, index2) along the slow and fast detector axes, respectively, or the displacement in millimetres along the slow and fast axes (center1, center2); cbf_get_detector_distance and cbf_get_detector_normal calculate the distance of the sample from the plane of the detector surface and the normal vector of the detector at pixel (0, 0), respectively; cbf_get_pixel_coordinates, cbf_get_pixel_normal and cbf_get_pixel_area calculate the coordinates, normal vector, and area and apparent area as viewed from the sample position of the pixel with the given indices, respectively.

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