[ Identification | Description | Input parameters | Output parameters | Links ]
FermiChopper
ComponentModels a fermi chopper with optional supermirror coated blades supermirror facilities may be disabled by setting m = 0, R0=0 Slit packages are straight. Chopper slits are separated by an infinitely thin absorbing material. The effective transmission (resulting from fraction of the transparent material and its transmission) may be specified. The chopper slit package width may be specified through the total width 'width' of the full package or the width 'w' of each single slit. The other parameter is calculated by: width = Nslit*w. The chopper needs a default velocity to calculate the initial value for an iterative calculation of TOF values. This can be specified by its velocity, energy, wavelength or wavevector. Example: FermiChopper(phase=-50.0, radius=0.04, nu=100, ymin=-0.04, ymax=0.04, w=0.00022475, Nslit=200.0, R0=0.0, Qc=0.02176, alpha=2.33, m=0.0, length=0.012, eff=0.95) Markus PoehlmannChristian Carbogno and Helmut Schober %VALIDATION Apr 2005: extensive external test, most problems solved (cf. 'Bugs') Validated by: K. Lieutenant limitations: no blade width used %BUGS - overestimates peak width for long wavelengths - may not give the right pulse position, shape and width for slit widths below 0.1 mm
Name | Unit | Description | Default |
---|---|---|---|
phase | deg | chopper phase at t=0 | 0 |
radius | m | chopper cylinder radius | 0.04 |
nu | Hz | chopper frequency | 100 |
ymin | m | lower y bound of cylinder | -0.04 |
ymax | m | upper y bound of cylinder | 0.04 |
w | m | width of one chopper slit | 0.00022475 |
Nslit | 1 | number of chopper slits | 200 |
R0 | 1 | low-angle reflectivity | 0.0 |
Qc | AA-1 | critical scattering vector | 0.02176 |
alpha | AA | slope of reflectivity | 2.33 |
m | 1 | m-value of material. Zero means completely absorbing. | 0.0 |
W | AA-1 | width of supermirror cut-off | 2e-3 |
length | m | channel length of the Fermi chopper | 0.012 |
eff | 1 | efficiency = transmission x fraction of transparent material | 0.95 |
zero_time | 1 | set time to zero: 0: no 1: once per half cycle | 0 |
width | m | optional total width of slit package | 0 |
verbose | 1 | set to 1 or 2 gives debugging information | 0 |
rad | - | , slit, alpham,Wi,dist,Vi | 0 |
slit | 0 | ||
alpham | 0 | ||
Wi | 0 | ||
dist | 0 | ||
Vi | 0 | ||
curvature | m-1 | Curvature of slits (1/radius of curvature). | 0 |
Name | Unit | Description | Default |
---|---|---|---|
FCVars | - | structure |
FermiChopper.comp
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[ Identification | Description | Input parameters | Output parameters | Links ]
Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Tue Sep 30 19:37:37 2008