The `Source_lab` Component

Laboratory x-ray source, using xraylib for all material data.

Identification

Author: Erik B. Knudsen (original Source_lab), xraylib port derived from it
Origin: Kgs. Lyngby
Date: May 2012 (original), 2026 (xraylib version)

Description

Model of a laboratory x-ray tube, generating x-rays by bombarding a target by electrons.
Given a input energy E0 of the electron beam, x-rays are emitted from the accessible emission lines
The geometry of the tube is assumed to be:
# The electron beam hits a slab of surface material surface at a right angle illuminating an area of width by height,
# where width is measured along the component X-axis.
# The centre of the electron beam at the anode surface is the origin of the component.
# The Z-axis of the component points at the centre of the exit window (focus_xw by focus yh)
placed at a distance dist from the origin.
# The angle between the Z-axis and the anode surface is the take_off angle.
For a detailed sketch of the geometry see the component manual.

The Bremsstrahlung emitted is modelled using the model of Kramer (1923) as restated in International
Tables of Crystallography C 4.1

Characteristic radiation (K-lines Ka1, Ka2, Kb1, Kb3) is modelled by Lorentzian (default) or Gaussian
energy profiles. Line energies, level widths (FWHM = K level width + final level width) and relative
intensities (radiative rates, strongest line = 1) are obtained from xraylib for ANY mono-atomic anode;
no datafile is needed. Lines that fall outside [Emin,Emax] are dropped.

Absorption of emitted x-rays while travelling through the target anode is included, using the xraylib
total mass attenuation coefficient (tabulated once in INITIALIZE on a log grid, with extra points
on both sides of every absorption edge, and interpolated log-log in TRACE).

Example: Source_lab(material="Cu",Emin=1, E0=80)
Legacy:  Source_lab(material_datafile="Cu.txt",Emin=1, E0=80)

Input parameters

Parameters in boldface are required; the others are optional.

Name	Unit	Description	Default
material	string	Anode element, symbol ("Cu", "W", ...) or atomic number as a string ("29").	"Cu"
width	m	Width of electron beam impinging on the anode.	1e-3
height	m	Height of electron beam impinging on the anode.	1e-3
thickness	m	Thickness of the anode material slab.	100e-6
E0	kV	Acceleration voltage of xray tube.	20
Emax	keV	Maximum energy to sample. Default (Emax=0) is to set it to E0.	0
Emin	keV	Minimum energy to sample.	1
focus_xw	m	Width of exit window.	5e-3
focus_yh	m	Height of exit window.	5e-3
take_off	deg	Take off angle of beam centre.	6
dist	m	Distance between centre of illuminated target and exit window.	1
tube_current	A	Electron beam current.	1e-3
frac	0-1	Fraction of statistic to use for Bremsstrahlung.	0.1
lorentzian	0/1	If nonzero Lorentzian (more correct) line profiles are used.	1
xwidth	m	Width of the anode material slab (0: practically infinite).	0
yheight	m	Height of the anode material slab (0: practically infinite).	0
exit_window_refpt	m	If set, the AT position and exit window will coincide (legacy behaviour).	0
material_datafile	string	Legacy parameter, kept for backward compatibility with Source_lab. Only the file NAME is used: the element is taken from it ("Cu.txt", "../data/Mo.txt" -> "Cu", "Mo"); the file is not read. If set, it overrides 'material'.	""

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

McXtrace - An X-ray ray-trace simulation package

The Source_lab Component

Identification

Description

Input parameters

Links

The `Source_lab` Component