The `Shell_p` Component

Single parabolic shell as part of a Wolter optic.

Identification

Site:
Author: Erik B Knudsen and Desiree D. M. Ferreira
Origin: DTU Physics, DTU Space
Date: Feb. 2016

Description

A single shell is simulated. The top and bottom are curved cylindrically
azimuthally. The sagital profile is defined by a parabola, which passes through the radii raidus_m
at z=0, and radius_p at zentry (<0).

To intersect the Wolter I plates we take advatage of the azimuthal symmetry and only consider the radial component
of the photon's wavevector.

Imperfect mirrors may be modelled using one of 4 models. In all cases the surface normal of the mirror
at the ideal mirror intersection point is perturbed before the exit vector is computed.
1. Longitudinal 1D. A perturbation angle is chosen from a uniform distribution with width waviness.
2. Isotropic 2D. The surface normal is perturbed by choosing an angle on a disc with radius waviness
3. Externally measured/computed data. We interpolate in a data-file consisting of blocks of dtheta/theta
with 1 block per energy. dtheta is a sampled angle offset from the nominal Fresnel grazing angle
theta.
4. Double gaussian. dtheta is chosen from one of two gaussian distributions. Either specular or off-specular, where the
widths (sigmas) are given by the tables in the file "wave_file". If the off-specular case the behaviour is similar
to 2D uniform case.

In the case of 3, the format of the data file should be:
#e_min=0.1
#e_max=15
#e_step=0.01
#theta_min=0.01
#theta_max=1.5
#theta_step=0.01
#dtheta_min=-0.02
#dtheta_max=0.02
#dtheta_step=0.001
1.0 0.9 0.8 0.75 ...
0.99 0.89 0.79 0.749 ...
...
#block 2 (energy data point 2)
1.0 0.9 0.8 0.75 ...
0.99 0.89 0.79 0.749 ...
...

I.e. one 2D data block per energy data point where rows represent the steps in nominal incident angle, and columns
represent the sampled granularity of the off-specular scattering.

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
radius_p	m	Ring radius of the upper (reflecting) plate of the shell at the edge furthest away from the focal point.
radius_m	m	Ring radius of the upper (reflecting) plate of the shell at the intersection with the hyperbolic section.
Z0	m	Distance between optics centre plane and focal spot (essentially focal length).
yheight	m	Height of the shell.
chamferwidth	m	Width of side walls.	0
gap	m	Gap between the plate and the intersection plane with the hyperbolic section.	0
zdepth			0
mirror_reflec		Data file containing reflectivities of the reflector surface (TOP).	""
bottom_reflec		Data file containing reflectivities of the bottom surface (BOTTOM).	""
wave_file			""
R_d		Default reflectivity value to use if no reflectivity file is given. Useful f.i. is one surface is reflecting and the others absorbing.	1
wave_model		Flag to choose waviness model. 1. longitudinal uniform, 2. 2D-uniform, 3. lorentzian sagittal, 4. double gaussian sagittal. See above for details.	0
waviness	rad	Waviness of the pore reflecting surface. The slope error is assumed to be uniformly distributed in the interval "[-waviness:waviness]".	0
verbose		If !=0 output extra info during simulation.	0

AT (	,	,		) RELATIVE
ROTATED (	,	,		) RELATIVE

McXtrace - An X-ray ray-trace simulation package

The Shell_p Component

Identification

Description

Input parameters

Links

The `Shell_p` Component