Perfect crystal with diamond or zincblende structure

Identification

Author: Anette Vickery, Andrea Prodi, Erik Knudsen

Origin: NBI

Date: April 2011

Version: 1.0

Description

Reads atomic formfactors from a data input file.
The PerfectCrystal code reflects ray in an ideal geometry, does not include surface imperfections or mosaicity
The crystal is positioned such that the long axis of the crystal surface coincides with
z-axis. The angle between the Bragg planes and the crystal surface is alpha
The algorithm:
Incoming photon's coordinates and direction (k-vector) are transformed into an elliptical reference frame
(elliptical parameters are calculated according to the mirror's position and its focusing distances and the * incident angle), the intersection point is then defined.
A new, reflected photon is then starting at the point of intersection.
Notation follows Tadashi Matsushita and Hiro-O Hashizume, X-RAY MONOCHROMATORS. Handbook on Synchrotron Radiation,North-Holland Publishing Company, 1:263–274, 1983.

Input parameters

Parameters in boldface are required;
the others are optional.

Name

Unit

Description

Default

form_factors

"FormFactors.txt"

material

"Si.txt"

R0

0

length

along z-axia

[m] length of the crystal

0.05

width

along x-axis

[m] width of the crystal

0.02

V

Å^3

unit cell volume160.1826

160.1826

h

1

k

1

l

1

alpha

alpha=0 for symmetric reflection, ie the Bragg planes are parallel to the crystal surface