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McStas: IncoherentPhonon_process

[ Identification | Description | Input parameters | Links ]

The IncoherentPhonon_process Component

A component to simulate inelastic scattering in the incoherent approximation Takes into account one, two, and three phonon scattering explicitly, and multi-phonon scattering (with n>4) via the saddle point method

Identification

  • Site:
  • Author: Victor Laliena
  • Origin: University of Zaragoza
  • Date: 06.11.2018

Description

Part of the Union components, a set of components that work together and thus
expects geometry and physics within McStas.
The use of this component requires other components to be used.

1) One specifies a number of processes using process components like this one
2) These are gathered into material definitions using Union_make_material
3) Geometries are placed using Union_box / Union_cylinder, assigned a material
4) A Union_master component placed after all of the above


Algorithm:
Described elsewhere, see e.g. https://doi.org/10.3233/JNR-190117

Input parameters

Parameters in boldface are required; the others are optional.
NameUnitDescriptionDefault
TKTemperature394
densityg/cm3Material density6.0
Mamuion mass50.94
sigmaCohbarnsCoherent scattering cross section0.0184
sigmaIncbarnsIncoherent scattering cross section5.08
DOSfnstringPath to the file that contains the DoSNULL
nphe_exact1Number of terms in the phonon expansion taken exact. Has to be between 1 and 3.1
nphe_approx1Number of terms in the phonon expansion taken approximate.0
approx1Approximation type: 0 gaussian, 1 saddle point0
mph_resum0/1Resumate the remaining terms of the phonon expansion via a saddle point: 0 No, 1 Yes0
nxs1Number of energy points at which the total cross sections are precomputed1000
kabsminA^-1Lower cut-off for the neutron wave-vector k0.1
kabsmaxA^-1Higher cut-off for the neutron wave-vector k25
interact_fraction1How large a part of the scattering events should use this process 0-1 (sum of all processes in material = 1)-1
init"init"
AT ( , , ) RELATIVE
ROTATED ( , , ) RELATIVE

Links


[ Identification | Description | Input parameters | Links ]

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


Last Modified: Tuesday, 16-Apr-2024 20:05:21 CEST
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