view article
Figure 3
Map of a small portion of the imaging detector centered on the true beam position, depicting conditional probability contours for the location of the direct beam, given an input beam position (black dot). This particular input beam position is 0.8 mm from the true value. Probabilities were determined using the projections of reciprocal-space points from one image onto (a) the b axis, (b) all three unit-cell axes, and (c) the top 20 directions identified by Fourier analysis. Panel (d) uses projections of reciprocal-space points from two images collected 90° apart in φ, onto the top 20 directions. The circle in panel (c) shows the largest search radius, 1.2 mm, which could have been used to find the true beam center given the input value. In panel (d) the largest useful search radius is at least 3.3 mm. The crystal is the same as used in Fig. 1[link], with a = 36, b = 65 and c = 84 Å. 1° oscillation exposures were collected with a detector distance of 130 mm and an X-ray wavelength of 1.0 Å.

Journal logoJOURNAL OF
APPLIED
CRYSTALLOGRAPHY
ISSN: 1600-5767
Volume 37| Part 3| May 2004| Pages 399-409
doi:10.1107/S0021889804005874
Follow J. Appl. Cryst.
Sign up for e-alerts
E-alerts
Follow J. Appl. Cryst. on Twitter
Twitter
Follow us on facebook
Facebook
Sign up for RSS feeds
RSS