[ Identification | Description | Examples | Input parameters | Links ]
Source_div ComponentThe routine is a rectangular neutron source, which has a gaussian or uniform divergent output in the forward direction. The neutron energy is distributed between lambda0-dlambda and lambda0+dlambda or between E0-dE and E0+dE. The flux unit is specified in n/cm2/s/st/energy unit (meV or Angs). In the case of uniform distribution (gauss=0), angles are uniformly distributed between -focus_aw and +focus_aw as well as -focus_ah and +focus_ah. For Gaussian distribution (gauss=1), 'focus_aw' and 'focus_ah' define the FWHM of a Gaussian distribution. Energy/wavelength distribution is also Gaussian. Example: Source_div(xwidth=0.1, yheight=0.1, focus_aw=2, focus_ah=2, E0=14, dE=2, gauss=0) %VALIDATION Feb 2005: tested by Kim Lefmann (o.k.) Apr 2005: energy distribution used in external tests of Fermi choppers (o.k.) Jun 2005: wavelength distribution used in external tests of velocity selectors (o.k.) Validated by: K. Lieutenant %BUGS distribution is uniform in (hor. and vert.) angle (relative to moderator normal), therefore not suited for large angles
| Name | Unit | Description | Default | |
| xwidth | m | Width of source | ||
| yheight | m | Height of source | ||
| focus_aw | deg | FWHM (Gaussian) or maximal (uniform) horz. width divergence | ||
| focus_ah | deg | FWHM (Gaussian) or maximal (uniform) vert. height divergence | ||
| E0 | meV | Mean energy of neutrons. | 0.0 | |
| dE | meV | Energy half spread of neutrons. | 0.0 | |
| lambda0 | AA | Mean wavelength of neutrons (only relevant for E0=0) | 0.0 | |
| dlambda | AA | Wavelength half spread of neutrons. | 0.0 | |
| gauss | 0|1 | Criterion: 0: uniform, 1: Gaussian distributions | 0 | |
| flux | 1/(s cm 2 st energy_unit) | flux per energy unit, Angs or meV | 1 |
| AT ( | , | , | ) RELATIVE | |||
|---|---|---|---|---|---|---|
| ROTATED ( | , | , | ) RELATIVE |
Source_div.comp.
[ Identification | Description | Examples | Input parameters | Links ]
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