MCNP geometry error

[MadGander]

I've got a small geometry related error in my MCNP input deck, corresponding to cell #14 (the outer edge of my detector model). This should be a quick fix, but I'm running into issues defining that particular union of surfaces. Any assistance is appreciated.

 

[Alex A]

This is a quick trick for the experiment cell,

14 0 -99 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 imp:p 1     $ surroundings

# negates a cell. So everything inside the surface that defines the boundary to the void (graveyard in your input file), but not any of the volumes defined by cells 1 through 12.

Using surfaces properly is probably better, but you can't half do it. It's perfect or it's broken.