[neutron-mc] Error in component Source_simple.comp ?

[Frederik Zilly]

Dear Mcstas experts,

The point which emits the neutron is calculated by:

  chi=2*PI*rand01();                          /* Choose point on source */
  r=sqrt(rand01())*radius;                    /* with uniform 
distribution. */
  x=r*cos(chi);
  y=r*sin(chi);

In my humble opinion, this will not lead to an uniform distribution over 
the sources surface.
Points near the center have greater probility than points with a higher 
radius.

Thanks,

Frederik.