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McStas: FZP_simple

[ Identification | Description | Input parameters | Links ]

The FZP_simple Component

Fresnel zone-plate as a thin object approximation.

Identification

  • Site:
  • Author: A Komar Ravn, and Erik B Knudsen
  • Origin: NBI/DTU
  • Date: Aug, 2015

Description

A simple phenomenological thin-object approximation of a Fresnel Zone Plate.
This component was adapted for neutrons from the original component
written for helium scattering.
The focal length of the Zone Plate is determined by the formula:
\[f = 2*r*dr/(lambda)\]
If a diffraction order other than 1 is wanted the focal distance is scaled accordingly.

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
radmRadius of the zone-plate.
drmWidth of the outermost ring-slit.
bs0radmRadius of the central blocking zone.0
ordermUse this diffaction order.1
eta Efficiency of the FZP. For neutrons and (order==1) typically {5...30}%. Overrides the sigma_x cross sections.0.1
sigma_absbarn2200 m/s absorption cross section.0
sigma_incbarnIncoherent scattering cross section.0
sigma_cohbarnCoherent scattering cross section.0
rho1
thicknessmThickness of the FZP. Note that the FZP still is modelled as a thin object. The thickness is used in conjunction with the sigma_x cross sections.0
gamma Duty cycle of the Zone plate - used merely for absorption estimation.0.5
AT ( , , ) RELATIVE
ROTATED ( , , ) RELATIVE

Links


[ Identification | Description | Input parameters | Links ]

Generated on 2023-09-19 20:01:36


Last Modified: Wednesday, 03-Jan-2024 19:59:10 CET
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