Refractive lens with absorption, incoherent scattering and surface imperfection.
Author: C. Monzat/E. Farhi/S. Desert/G. Euzen
Refractive Lens with absorption, incoherent scattering and surface imperfection.
Geometry may be:
spherical (use r1 and r2 to specify radius of curvature),
planar (use phiy1 and phiy2 to specify rotation angle of plane w.r.t beam)
parabolic (use focus1 and focus2 as optical focal length).
Optionally, you can specify the 'geometry' parameter as a OFF/PLY file name.
The complex geometry option handles any closed non-convex polyhedra.
It computes the intersection points of the neutron ray with the object
transparently, so that it can be used like a regular sample object.
It supports the PLY, OFF and NOFF file format but not COFF (colored faces).
Such files may be generated from XYZ data using:
qhull < coordinates.xyz Qx Qv Tv o > geomview.off
and viewed with geomview or java -jar jroff.jar (see below).
The lens cross-section is seen as a 2*radius disk from the beam Z axis, except
when a 'geometry' file is given.
Usually, you should stack more than one of these to get a significant effect
on the neutron beam, so-called 'compound refractive lens'.
The focal length for N lenses with focal 'f' is f/N, where f=R/(1-n)
and R = r/2 for a spherical lens with curvature radius 'r'
R = focus for a parabolic lens with focal of the parabola
and n = sqrt(1-(lambda*lambda*rho*bc/PI)) with
bc = sqrt(fabs(sigma_coh)*100/4/PI)*1e-5
rho = density*6.02214179*1e23*1e-24/weight
Common materials: Should have high coherent, and low incoherent and absorption cross sections
Be: density=1.85, weight=9.0121, sigma_coh=7.63, sigma_inc=0.0018,sigma_abs=0.0076
Pb: density=11.115,weight=207.2, sigma_coh=11.115,sigma_inc=0.003, sigma_abs=0.171
Pb206: sigma_coh=10.68, sigma_inc=0 , sigma_abs=0.03
Pb208: sigma_coh=11.34, sigma_inc=0 , sigma_abs=0.00048
Zr: density=6.52, weight=91.224, sigma_coh=6.44, sigma_inc=0.02, sigma_abs=0.185
Zr90: sigma_coh=5.1, sigma_inc=0 , sigma_abs=0.011
Zr94: sigma_coh=8.4, sigma_inc=0 , sigma_abs=0.05
Bi: density=9.78, weight=208.98, sigma_coh=9.148, sigma_inc=0.0084,sigma_abs=0.0338
Mg: density=1.738, weight=24.3, sigma_coh=3.631, sigma_inc=0.08, sigma_abs=0.063
MgF2: density=3.148, weight=62.3018,sigma_coh=11.74, sigma_inc=0.0816,sigma_abs=0.0822
diamond: density=3.52, weight=12.01, sigma_coh=5.551, sigma_inc=0.001, sigma_abs=0.0035
Quartz/silica: density=2.53, weight=60.08, sigma_coh=10.625,sigma_inc=0.0056,sigma_abs=0.1714
Si: density=2.329, weight=28.0855,sigma_coh=2.1633,sigma_inc=0.004, sigma_abs=0.171
Al: density=2.7, weight=26.98, sigma_coh=1.495, sigma_inc=0.0082,sigma_abs=0.231
density=2.2, weight=50.007, sigma_coh=13.584,sigma_inc=0.0026,sigma_abs=0.0227
Organic molecules with C,O,H,F
Example: Lens(r1=0.025,r2=0.025, thickness=0.001,radius=0.0150)
parabolic shape is not fully validated yet, but should do still...
WARNING: This is a contributed Component.
Parameters in boldface are required;
the others are optional.
radius of the first circle describing the lens. r>0 means concave face, r<0 means convex, r=0 means plane
radius of the second circle describing the lens r>0 means concave face, r<0 means convex, r=0 means plane
focal of the first parabola describing the lens
focal of the second parabola describing the lens
angle of plane1 (r1=0) around y vertical axis
angle of plane2 (r2=0) around y vertical axis
thickness of the lens between its two surfaces
radius of the lens section, e.g. beam size.
coherent cross section
incoherent cross section
thermal absorption cross section
density of the material for the lens
molar mass of the material
MC Probability for scattering the ray; otherwise transmit
vertical angle to forward focus after scattering
horizontal angle to forward focus after scattering
root mean square roughness of the surface
Name of an Object File Format (OFF) or PLY file for complex geometry. The OFF/PLY file may be generated from XYZ coordinates using qhull/powercrust