McStas logo McStas - A neutron ray-trace simulation package ILL; PSI; ESS Niels Bohr Institute DTU Physics NEXMAP


About McStas
 Conditions of use
 Project funding

 Linux Install (deb/rpm)
 Mac OS X Install
 Unix Install (src code)
 Windows Install
 Other Downloads (share)

Mailing list

Search web/mailinglist

 McStas manual
 Known problems
 C Compilers




Report bugs


McStas Ubuntu live-dvd

McStas: Sans_spheres Component

[ Identification | Description | Input parameters | Output parameters | Links ]

The Sans_spheres Component

Sample for Small Angle Neutron Scattering - hard spheres in thin solution, mono disperse.


  • Author: P. Willendrup, K. Lefmann, L. Arleth
  • Origin: Risoe
  • Date: 19.12.2003
  • Version:(Unknown)
  • Modification history:
    • KL, 7 June 2005


Sample for use in a SANS instrument, models hard, mono disperse spheres in thin solution.
  The shape of the sample may be a filled box with dimensions
  xwidth, yheight, zdepth, a cylinder with dimensions radius and yheight,
  a filled sphere with radius.

Example: Sans_spheres(R = 100, Phi = 1e-3, Delta_rho = 0.6, sigma_abs = 50, xwidth=0.01, yheight=0.01, zdepth=0.005)

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
R AA Radius of scattering hard spheres 100
Phi 1 Particle volume fraction 1e-3
Delta_rho fm/AA^3 Excess scattering length density 0.6
sigma_abs m^-1 Absorption cross section density at 2200 m/s 0.05
xwidth m horiz. dimension of sample, as a width 0
yheight m vert . dimension of sample, as a height for cylinder/box 0
zdepth m depth of sample 0
radius m Outer radius of sample in (x,z) plane for cylinder/sphere 0
target_x 0
target_y m position of target to focus at 0
target_z 6
target_index 1 Relative index of component to focus at, e.g. next is +1 0
focus_xw m horiz. dimension of a rectangular area 0
focus_yh m vert. dimension of a rectangular area 0
focus_aw deg horiz. angular dimension of a rectangular area 0
focus_ah deg vert. angular dimension of a rectangular area 0
focus_r m Detector (disk-shaped) radius 0

Output parameters

Name Unit Description Default


  • Source code for Sans_spheres.comp.
  • The test/example instrument SANS.instr.
  • Some alternative implementations exist as contributed components.

[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <> / Mon Jun 26 12:27:17 2017

Last Modified: Monday, 26-Jun-2017 14:27:17 CEST
Search website mailinglist archive GitHub repos