The `Lens` Component

Refractive lens with absorption, incoherent scattering and surface imperfection.

Identification

Author: C. Monzat/E. Farhi/S. Desert/G. Euzen
Origin: ILL/LLB
Date: 2009
Version: $Revision 1.0$ - differs from 1.12b version only by corrected typo in author name

Description

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) 
  or parabolic (use focus1 and focus2 as optical focal length). 
The lens cross-section is seen as a 2*radius disk from the beam Z axis.
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.

Common material: 
  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
  perfluoropolymer

Example: Lens(r1=0.025,r2=0.025, thickness=0.001,radius=0.0150)

%BUGS
parabolic shape is not fully validated yet, but should do still...

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
r1	m	radius of the first circle describing the lens. r>0 means concave face, r<0 means convex, r=0 means plane	0
r2	m	radius of the second circle describing the lens r>0 means concave face, r<0 means convex, r=0 means plane	0
focus1	m	focal of the first parabola describing the lens	0
focus2	m	focal of the second parabola describing the lens	0
phiy1	deg	angle of plane1 (r1=0) around y vertical axis	0
phiy2	deg	angle of plane2 (r2=0) around y vertical axis	0
thickness	m	thickness of the lens between its two surfaces	0.001
radius	m	radius of the lens section, e.g. beam size	0.015
sigma_coh	barn	coherent cross section	11.74
sigma_inc	barn	incoherent cross section	0.0816
sigma_abs	barn	thermal absorption cross section	0.0822
density	g/cm3	density of the material for the lens	3.148
weight	g/mol	molar mass of the material	62.3018
p_interact	1	MC Probability for scattering the ray; otherwise transmit	0.1
focus_aw	deg	vertical angle to forward focus after scattering	10
focus_ah	deg	horizontal angle to forward focus after scattering	10
RMS	Angs	root mean square roughness of the surface	0

Output parameters

Name	Unit	Description	Default
rho
bc
my_s
my_a_v
mean_n
events

The Lens Component

Identification

Description

Input parameters

Output parameters

Links

The `Lens` Component