Models a rectangular guide tube centered on the Z axis. The entrance lies
in the X-Y plane.
The guide may be tapered, and may have vertical subdivisions (used for
There is a special rotating mode in order to approximate a Fermi Chopper
behaviour, in the case the neutron trajectory is nearly linear inside the
chopper slits, i.e. the neutrons are fast w/r/ to the chopper speed.
Slits are straight, but may be super-mirror coated. In this case, the
component is NOT centered, but located at its entry window. It should then
be shifted by -l/2.
Example: Guide_channeled(w1=0.1, h1=0.1, w2=0.1, h2=0.1, l=2.0,
R0=0.99, Qcx=0.0219, Qcy=0.0219, alphax=6.07, alphay=6.07, W=0.003, nslit=1,
d=0.0005, mx=1, my=1)
This component does not work with gravitation on. Use Guide_gravity.
This component does not work in multichannel focusing geometry.
Example values: mx=4 my=2 Qcx=Qcy=0.0219 W=1/300 alphax=alphay=6.49 R0=1
Parameters in boldface are required;
the others are optional.
Width at the guide entry
Height at the guide entry
Width at the guide exit
Height at the guide exit
Length of guide
Critical scattering vector
Slope of reflectivity
m-value of material. Zero means completely absorbing.
 Number of channels in the guide
Thickness of subdividing absorbing walls
Critical scattering vector for left and right vertical mirrors in each channel
Critical scattering vector for top and bottom mirrors
Slope of reflectivity for left and right vertical mirrors in each channel
Slope of reflectivity for top and bottom mirrors
Width of supermirror cut-off for all mirrors
m-value of material for left and right vertical mirrors in each channel. Zero means completely absorbing.
m-value of material for top and bottom mirrors. Zero means completely absorbing.
Rotation frequency (round/s) for Fermi Chopper approximation