Hi all,

I am using GENC operator to compute the distance to the specified energy fraction for a line like shaped beam and would like to do the same when using an extended source. My understanding is that I should use XENC with extended sources, which I can define by IMA files, and that XENC works like GENC operator.

Just to check, I have set Filed Size = 0 (point source) on the Extended Source Encircled Energy tab and want to find the distance for y slit width for energy fraction = 1. All other parameters are the same, in both Geometric Encircled Energy and Extended Source Encircled Energy. I expected the same distance for the y slit width from GENC and XENC but they give different values.

Can someone explain why I am getting different results and how to compute the y slit width distance for given energy fraction with an extended source ?

Marko