檢視 $Light intensity region TBLR 的原始碼

is a special function to define the side wall of 4 regions to collect the light output

 $Light_intensity_region_TBLR
 X_Left  X_middle X_right Y_top Y_middle Y_bottom

When the light leaves the simulation objects, we put a square box larger than the simulation objects to collect the light output. The program will record the position photon hitting the sidewall. This ranges is decided by  X_Left  X_right Y_top Y_bottom. Unit is (cm).   X_middle and Y_middle is definition the separation point where the photon is belong to.