A simple analytical Soller collimator (with triangular transmission).
Author: Kristian Nielsen
Date: August 1998
GA, June 1999, added transmission
Soller collimator with rectangular opening and specified length. The
transmission function is an average and does not utilize knowledge of the
actual neutron trajectory. A zero divergence disables collimation (then the
component works as a double slit).
Example: Collimator_linear(xmin=-0.1, xmax=0.1, ymin=-0.1, ymax=0.1, length=0.25, divergence=40,transmission=0.7)
Parameters in boldface are required;
the others are optional.
Lower x bound on slits
Upper x bound on slits
Lower y bound on slits
Upper y bound on slits
Width of slits
Height of slits
Distance between input and output slits
calculated as atan(d/length), where d is the blade spacing