\section{PSD\_monitor\_4PI: A 4 PI steradian spherical monitor.}
\index{Monitor!$4 pi$}
\mcdoccomp{monitors/PSD_monitor_4PI.parms}

\textbf{PSD\_monitor\_4PI} is an unphysical idealized component. It takes on the shape of
a complete sphere with a given \textit{radius}, records the longitude and latitude of 
photon rays as the pass through the sphere.
The sphere is binned in constant spaced bins in longitude and latitude. This has the consequence
that the image will be distorted when plotted onto a plane, much like projections of a world map. 

The output from \texttt{PSD\_monitor} is the integrated counts, $n, I, M_2$,
as well as
three two-dimensional arrays of counts: $n(x,y), I(x,y), M_2(x,y)$.
The arrays are written to a file, \verb+filename+, and can be read e.g. by the tool
\textbf{mxplot}, see the system manual.

