/******************************************************************************* * * McStas, neutron ray-tracing package * Copyright 1997-2002, All rights reserved * Risoe National Laboratory, Roskilde, Denmark * Institut Laue Langevin, Grenoble, France * * Component: Beamstop * * %ID * * Written by: Kristian Nielsen * Date: January 2000 * Origin: Risoe * * Rectangular/circular beam stop. * * %D * A simple rectangular or circular beam stop. * Infinitely thin and infinitely absorbing. * The beam stop is by default rectangular. You may either * specify the radius (circular shape), or the rectangular bounds. * * Example: Beamstop(xmin=-0.05, xmax=0.05, ymin=-0.05, ymax=0.05) * Beamstop(radius=0.1) * * %PAR * * INPUT PARAMETERS * * radius: [m] radius of the beam stop in the z=0 plane, centered at Origo * xmin: [m] Lower x bound * xmax: [m] Upper x bound * ymin: [m] Lower y bound * ymax: [m] Upper y bound * xwidth: [m] Width of beamstop (x). Overrides xmin, xmax. * yheight: [m] Height of beamstop (y). Overrides ymin, ymax. * * %END *******************************************************************************/ DEFINE COMPONENT Beamstop DEFINITION PARAMETERS () SETTING PARAMETERS (xmin=-0.05, xmax=0.05, ymin=-0.05, ymax=0.05, xwidth=0, yheight=0, radius=0) OUTPUT PARAMETERS () /* Neutron parameters: (x,y,z,vx,vy,vz,t,sx,sy,sz,p) */ INITIALIZE %{ if (xwidth > 0) { xmax = xwidth/2; xmin = -xmax; } if (yheight > 0) { ymax = yheight/2; ymin = -ymax; } if (xmin == 0 && xmax == 0 && ymin == 0 & ymax == 0 && radius == 0) { fprintf(stderr,"Beamstop: %s: Error: give geometry\n", NAME_CURRENT_COMP); exit(-1); } %} TRACE %{ double Time = t; ALLOW_BACKPROP; PROP_Z0; Time = t - Time; if (((Time>=0) && ((radius!=0) && (x*x + y*y <= radius*radius))) || ((Time>=0) && (radius==0) && (x>xmin && xymin && y