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Figure 7
Method of evaluating the BT for a more realistic two-dimensional system. (a) Sketch of the system, consisting of a moderator of height m illuminating a guide of height g starting at a distance L1 from the moderator, where g is greater than m. A sample of height s is placed at a distance L2 from the end of the guide. The guide is assumed to be long compared with the gaps L1 and L2. (b) Acceptance diagrams for the positions labelled A, B and C in panel (a), corresponding to the guide entrance, guide exit and sample position, respectively. The blue areas show the areas of phase space at those positions. The purple rectangle shows the phase-space acceptance of the guide, and the intersection of the blue and purple areas is outlined in green. The yellow rectangle shows the area of phase space for which we wish to evaluate the BT. The intersection of the blue and yellow areas is outlined in red.

Journal logoJOURNAL OF
APPLIED
CRYSTALLOGRAPHY
ISSN: 1600-5767
Volume 51| Part 2| April 2018| Pages 264-281
https://doi.org/10.1107/S1600576718002406
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