Recent content by MadGander

Hi all, I'm modeling an HPGe detector and want to determine the amount of downscatter that contributes to a Ba-133 spectra. I'm using a PTRAC card to filter scattering events that occur in my Ta4C3 shield that contribute to tally 1 (surface fluence across the front face of the detector). I want...

Hi all, I'm attempting to simulate a very specific setup in MCNP. I want to know the fraction of particles contributing to a surface tally that previously interacted (scattered) with a specified cell. I'm currently doing this via the PTRAC card as well as FILTER. Currently, my PTRAC is...

Hello, I'm attempting to model a 300x300x300 cm room in MCNP with a doorway and walk-in section, but I'm struggling with some of the cell definitions, particularly in the Z plane. I've attached the input deck below. It is fairly short, so it's probably going to be a relatively quick fix. Any...

Hi all, I'm working with an MCNP deck with 4 embedded universes and am having trouble with a srctp error when attempting to run the deck. I had the simplified version with the larger two universes running fine, but when I try to add in the third and fourth layers I experience this error. Would...

Hi folks, I'm attempting to define an SDEF cone source but am getting tripped up in the SI/SP/SB distributions. I need all particles to be generated at angles within the cone, with all angles in the cone having equal probability. I feel like this should be relatively simple to define since the...

I'm trying to resolve two separate fatal errors in my MCNP deck. One is claiming that I'm mixing atom and weight fractions within a single material card, which I'm clearly not if you take a peek at the material definitions. The other is saying that I have an odd number of entries, indicating...

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.

Thanks for the help. I have another mcnp related question regarding the MT card. I'm using "MT u-uo2.40t o-uo2.40t" and getting a "xs is missing from xsdir_mcnp6.1" fatal error. I'm running the input deck on version 6.3, so based on the error I'm assuming that the .40t table is not compatible...

I'm trying to rotate an RPP 45 degrees around the y axis (BUT NOT THE ORIGIN Y AXIS, rather the y axis at x=a, z=b). Is there a way to do this in MCNP? I've tried every single possible combination of angles and inputs to no avail. Again, I have an RPP that is not centered at the origin and I...

Hi all, I'm working on building a fuel compact using hexagonal lattice cells, but I'm running into trouble with the RHP/HEX definition. The deck is error free, but for one reason or another the lattice cell isn't replicating along the Z axis.. only the X and Y, or at least this is what I'm...

Thread can be closed. I ended up ditching this route and am pursuing a different method.

Im trying to model a TRISO fuel compact using BCC lattice cells. I'm focusing specifically on the x-y plane to produce a cylindrical geometry. Depending on exact location, the periphery cells have some sort of pseudo-BCC structure to form the outer edge of the compact. Because of this, the...

I'm looking for someone to help troubleshoot my MCNP input deck. I'm getting a geometry related error most likely due to some sort of surface overlap. Haven't been able to identify the issue myself, so I'd appreciate a secondary check. Thanks!

I'm wondering how exactly MCNP calculates an f6 tally? I'm trying to compare a theoretical result with an MCNP f6 tally (MeV/g). I have an initial energy spectrum and a thin layer of lead that attenuates the x-rays. Using the attenuation coefficient at each energy (bin width of 0.5 kev from...

My results were calculated using Python and don't directly pertain to MCNP. Wasn't sure exactly where to post this question, but I guess you could move it over to the Nuke section. Thanks.