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/*****************************************************************************
*
* McStas, neutron ray-tracing package
* Copyright 1997-2024, All rights reserved
* Technical University of Denmark, Kongens Lyngby, Denmark
* Institut Laue Langevin, Grenoble, France
*
* Component: Spin_random
*
* %I
* Written by: Michael Schneider (SNAG)
* Date: 2024
* Origin: SNAG
*
* Set a random polarisation
*
* %D
*
* This component has no physical size or extent, it simply asigns the neutron
* ray polarisation randomly to either spin-up or spin-down.
*
* %P
* INPUT PARAMETERS:
*
* CALCULATED PARAMETERS:
*
* %E
*******************************************************************************/
DEFINE COMPONENT Spin_random
SETTING PARAMETERS ()
/* STATE PARAMETERS (x,y,z,vx,vy,vz,t,s1,s2,p) */
/* POLARISATION PARAMETERS (sx,sy,sz) */
TRACE
%{
int S_check;
sx = 0.0;
sz = 0.0;
do
{
sy = randpm1();
S_check = 0;
if (sy < 0)
{sy = -1.0; S_check=1;}
if (sy > 0)
{sy = 1.0; S_check=1;}
}while (S_check == 0);
%}
END
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