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

 Other Downloads (share)

Mailing list

Search web/mailinglist

 Wiki (GitHub)
 McStas manual


Report bugs (GitHub)

Code-repository (GitHub)

McStas: SESANS_Delft Instrument at Reactor_Institute_Delft

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

The SESANS_Delft Instrument

Idealised SESANS instrument using magnetised foil flippers with realistic sample


  • Site: Reactor_Institute_Delft
  • Author: Wim Bouwman (, Peter Willendrup and Erik Knudsen
  • Origin: Delft University of Technology
  • Date: December 2019
  • Version:(Unknown)


A full description of the instrument can be found in J. Appl. Cryst. (2021) V. 54
The instrument has the bare essentials to simulate the Larmor precession of the neutron spins in the foil flippers and the 
geometry and wavelength distribution of the SESANS in Delft as described in
Rev. Sci. Instrum. 76, 033901 (2005)
An essential component is the realistic SANS sample, describing both the scattered and transmitted neutron, including multiple scattering.
In one scattering simulation both the up- and down intensities are simulated.
For a full SESANS scan the applied magnetic field By has to be scanned.
In principle the sample can be removed to study the empty beam instrument, which with this idealised setup have perfect polarisation.
It is possible to monitor the evolution of the polarisation with several polarisation monitors that have beeen commented in this version.
The foil-angle, thickness and wavelength yield now matched parameters to have the SESANS working. 
These parameter and the sphere radius match now with the magnetic fields below to get a good measurement range.

Example: SESANS_Delft -n 1000000 -N 31 L0=2.165 DL=0.02 By=0,0.0468

Input parameters

Parameters in boldface are required; the others are optional.
Name Unit Description Default
L0 AA nominal wavelength 2.165
DL AA wavelength band width 0.02
By T Applied magnetic field in foil flippers 4.68e-3


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

Generated automatically by McDoc, Peter Willendrup <> / Wed Jan 12 15:13:21 2022

Last Modified: Wednesday, 12-Jan-2022 16:13:21 CET
Search website mailinglist archive GitHub repos