We put a graphite disk source between two .01 inch disks that have the same radius as our baked graphite disks.
Then, the two surfaces were put 1 cm apart with the disk source centered between them.
Tallying .511 MeV photons across the total disk area and the near surfaces of the disks, we ran MCNP from a 1 cm to 4 cm separation with a .5 cm step.
The plot is tallies per particle of the near surface of the disk only as a function of seperation.
Analyization of the data is still taking place to help explain the unexpected results.

MCNP Near Side