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McStas: V_sample

[ Identification | Description | Input parameters | Links ]

The V_sample Component

Vanadium sample.

Identification

  • Site:
  • Author: Kim Lefmann and Kristian Nielsen
  • Origin: Risoe
  • Date: 15.4.98

Description

A Double-cylinder shaped incoherent scatterer (a V-sample)
with both elastic and quasielastic (Lorentzian) components.
No multiple scattering. Absorbtion included.
The shape of the sample may be a box with dimensions xwidth, yheight, zthick.
The area to scatter to is a disk of radius 'focus_r' situated at the target.
This target area may also be rectangular if specified focus_xw and focus_yh
or focus_aw and focus_ah, respectively in meters and degrees.
The target itself is either situated according to given coordinates (x,y,z),
or defined with the relative target_index of the component to focus
to (next is +1).
This target position will be set to its AT position. When targeting to
centered components, such as spheres or cylinders, define an Arm component
where to focus to.

Example: V_sample(radius_i=0.001,radius_o=0.01,h=0.02,focus_r=0.035,pack=1,
target_index=1)

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
radiusmOuter radius of sample in (x,z) plane0
thicknessmThickness of outer wall0
zdepthmdepth of box sample0
VcUnit cell volume [AA^3]13.827
sigma_absbarnsAbsorbtion cross section pr. unit cell5.08
sigma_incbarnsIncoherent scattering cross section pr. unit cell5.08
radius_imradius-thickness0
radius_omSame as radius0
hmSame as yheight0
focus_rmRadius of disk containing target. Use 0 for full space0
pack1Packing factor1
frac1MC Probability for scattering the ray; otherwise penetrate1
f_QE1Fraction of quasielastic scattering (rest is elastic)0
gamma1Lorentzian width of quasielastic broadening (HWHM)0
target_x0
target_ymposition of target to focus at0
target_z0
focus_xwmhoriz. dimension of a rectangular area0
focus_yhmvert. dimension of a rectangular area0
focus_awdegangular width dimension of a rectangular area0
focus_ahdegangular height dimension of a rectangular area0
xwidthmhoriz. dimension of sample0
yheightmvert. dimension of sample0
zthickmSame as zdepth0
rad_spheremRadius for a spherical sample0
sig_abarnsSame as sigma_abs0
sig_ibarnsSame as sigma_inc0
V0Same as Vc [AA^3]0
target_index1relative index of component to focus at, e.g. next is +10
multiples1Apply crude estimate for multiple scattering1
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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