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/*******************************************************************************
*
* McStas, neutron ray-tracing package
* Copyright (C) 1997-2009, All rights reserved
* Risoe National Laboratory, Roskilde, Denmark
* Institut Laue Langevin, Grenoble, France
*
* Component: PSD_monitor_4PI_spin
*
* %I
* Written by: Erik B Knudsen
* Date: April 17, 2010s
* Origin: DTU
*
* Spherical position-sensitive detector with spin weighting
*
* %D
* An (n times m) pixel spherical PSD monitor using a cylindrical projection.
* Mostly for test and debugging purposes.
*
* Example: PSD_monitor_4PI(radius=0.1,
nx=90, ny=90, filename="Output.psd")
*
* %P
* INPUT PARAMETERS:
*
* radius: [m] Radius of detector
* nx: [1] Number of pixel columns
* ny: [1] Number of pixel rows
* filename: [str] Name of file in which to store the detector image
* restore_neutron: [1] If set, the monitor does not influence the neutron state x
* mx: [1] x-component of spin reference-vector
* my: [1] y-component of spin reference-vector
* mz: [1] z-component of spin reference-vector
*
* CALCULATED PARAMETERS:
*
* PSD_N: Array of neutron counts
* PSD_p: Array of neutron weight counts
* PSD_p2: Array of second moments
*
* %L
* <A HREF="http://neutron.risoe.dk/mcstas/components/tests/powder/">Test
* results</A> (not up-to-date).
*
* %E
*******************************************************************************/
DEFINE COMPONENT PSD_monitor_4PI_spin
SETTING PARAMETERS (int nx=90, int ny=90, radius, string filename=0, int restore_neutron=0, mx=0, my=1, mz=0)
DECLARE
%{
DArray2d PSD_N;
DArray2d PSDu_p;
DArray2d PSDd_p;
DArray2d PSDu_p2;
DArray2d PSDd_p2;
%}
INITIALIZE
%{
PSD_N = create_darr2d(nx, ny);
PSDu_p = create_darr2d(nx, ny);
PSDd_p = create_darr2d(nx, ny);
PSDu_p2 = create_darr2d(nx, ny);
PSDd_p2 = create_darr2d(nx, ny);
// Use instance name for monitor output if no input was given
if (!strcmp(filename,"\0")) sprintf(filename,"%s",NAME_CURRENT_COMP);
%}
TRACE
%{
double t0, t1, phi, theta;
int i,j;
if(sphere_intersect(&t0, &t1, x, y, z, vx, vy, vz, radius) && t1 > 0)
{
if(t0 < 0)
t0 = t1;
/* t0 is now time of intersection with the sphere. */
PROP_DT(t0);
phi = atan2(x,z);
i = floor(nx*(phi/(2*PI)+0.5));
if(i >= nx)
i = nx-1; /* Special case for phi = PI. */
else if(i < 0)
i = 0;
theta=asin(y/radius);
j = floor(ny*(theta+PI/2)/PI+0.5);
if(j >= ny)
j = ny-1; /* Special case for y = radius. */
else if(j < 0)
j = 0;
/*look at spin-down neutrons*/
double n_up=(1+scalar_prod(sx,sy,sz,mx,my,mz))*p/2;
/*look at spin-down neutrons*/
double n_down=(1-scalar_prod(sx,sy,sz,mx,my,mz))*p/2;
double n_up2 = n_up*n_up;
double n_down2 = n_down*n_down;
#pragma acc atomic
PSD_N[i][j] = PSD_N[i][j] + 1;
#pragma acc atomic
PSDu_p[i][j] = PSDu_p[i][j] + n_up;
#pragma acc atomic
PSDu_p2[i][j] = PSDu_p2[i][j] + n_up2;
#pragma acc atomic
PSDd_p[i][j] = PSDd_p[i][j] + n_down;
#pragma acc atomic
PSDd_p2[i][j] = PSDd_p2[i][j] + n_down2;
SCATTER;
}
if (restore_neutron) {
RESTORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
}
%}
SAVE
%{
char title[256];
char fn[256];
snprintf(title,256,"4PI PSD Monitor spin %s (parallel to m=%g,%g,%g).","up",mx,my,mz);
snprintf(fn,256,"%s.up",filename);
DETECTOR_OUT_2D(
title,
"Longitude [deg]",
"Lattitude [deg]",
-180, 180, -90, 90,
nx, ny,
&PSD_N[0][0],&PSDu_p[0][0],&PSDu_p2[0][0],
fn);
snprintf(title,256,"4PI PSD Monitor spin %s (antiparallel to m=%g,%g,%g).","down",mx,my,mz);
snprintf(fn,256,"%s.down",filename);
DETECTOR_OUT_2D(
title,
"Longitude [deg]",
"Lattitude [deg]",
-180, 180, -90, 90,
nx, ny,
&PSD_N[0][0],&PSDd_p[0][0],&PSDd_p2[0][0],
fn);
%}
FINALLY %{
destroy_darr2d(PSD_N);
destroy_darr2d(PSDu_p);
destroy_darr2d(PSDd_p);
destroy_darr2d(PSDu_p2);
destroy_darr2d(PSDd_p2);
%}
MCDISPLAY
%{
magnify("");
circle("xy",0,0,0,radius);
circle("xz",0,0,0,radius);
circle("yz",0,0,0,radius);
%}
END
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