[ Identification | Description | Input parameters | Links ]
Source_lab ComponentModel 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)
| 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 |
Source_lab.comp.
[ Identification | Description | Examples | Input parameters | Links ]
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