Is it possible to use TR or TRCL to translate an F4 or FMESH4 tally in MCNP6.2?

  • Thread starter 19matthew89
  • Start date
  • Tags
    Mcnp
In summary, you can use TRCL to translate a cell, but you need to be careful about the bounds of the FMESH.
  • #1
19matthew89
47
12
TL;DR Summary
Is it possible to use TR card to translate a segmented or a mesh tally?
Hi everyone,
I'd like to know if it is possible to use TR or TRCL to translate an F4 or FMESH4 tally.

Let me better explain: I have a cell, centered at 0,0,0 and for this cell I set up a segmentation tally along z-axis with a series of planes orthogonal to the z-axis. Moreover, I have also set up a Cartesian mesh tally with FMESH4.
Now I'd like to translate the cell along the z-axis (and later also rotate). This can be done easily with TRCL card but may I apply the same transformation to the F4 segmented tally and FMESH4 tally that I set up for the cell at 0,0,0? so that, for instance, I do not need to define planes orthogonal to the z-axis or the mesh at different heights but such that the tallies on the translated cell inherit, somehow, the structure of the original tallies?

The section of the manual about tallies in repeated structure is mainly focused on lattices or elements of the universes and not about segmentation or meshes.

Thanks in advance
 
  • Like
Likes Grelbr42
Engineering news on Phys.org
  • #2
You don't use the TR card to move the FMESH. You use the origin and axis entries on the FMESH. That let's you specify the origin of the mesh, the x-axis of the mesh, and the orientation of the mesh y-axis relative to the x-axis. If you were doing a cylindrical mesh then you specify the z-axis of the cylinder and the location of the zero of angle around the cylinder.

Note: Read the manual about the bounds of the FMESH very carefully when you are using this feature. Try it out a few times on runs with very small number of particles. The manual is kind of confusing, at least for me, on how the bounds are affected by the origin.
 
  • Like
Likes 19matthew89
  • #3
Grelbr42 said:
You don't use the TR card to move the FMESH. You use the origin and axis entries on the FMESH. That let's you specify the origin of the mesh, the x-axis of the mesh, and the orientation of the mesh y-axis relative to the x-axis. If you were doing a cylindrical mesh then you specify the z-axis of the cylinder and the location of the zero of angle around the cylinder.

Note: Read the manual about the bounds of the FMESH very carefully when you are using this feature. Try it out a few times on runs with very small number of particles. The manual is kind of confusing, at least for me, on how the bounds are affected by the origin.
Yeah! I already got in that kind of situation with the origin so now I know how to deal with that 😅 Indeed for mesh tally I already did and it was fast enough and not a big deal.
It would be more useful in the case of the of F4 tallies. With my current setup everything is anyway pretty easy but, but I'm afraid it might be a bit more bothersome when cells are going to be tilted.
 
  • #4
Hi 19matthew89,

your post about the "trans" coomand was very interesting for me!
Please, could you suggest a way to combine linear and rotated tallies?

Thank you
Laura
 
  • #5
lauraB said:
Hi 19matthew89,

your post about the "trans" coomand was very interesting for me!
Please, could you suggest a way to combine linear and rotated tallies?

Thank you
Laura
Hi Laura,
I don't exactly understand what you mean...
Every TR card (which has to follow a TRANS key word) is to be defined with a linear displacement vector:

TRn o1 o2 o3 xx’ yx’ zx’ xy’ yy’ zy’ xz’ yz’ zz’ m

with o1, o2, and o3 displacement vector.

Is this that you mean with "linear and rotated tallies"?

Cheers
 

1. What are TR and TRCL transformations in MCNP6.2?

TR (Translation) and TRCL (Translation/Rotation) are geometric transformation cards used in the Monte Carlo N-Particle (MCNP) simulation software. TR is used to translate a geometry or a component in space, while TRCL can both translate and rotate geometries. These transformations help in manipulating the position and orientation of components in a nuclear simulation without the need to redefine the geometry.

2. Can TR or TRCL be used to translate an F4 or FMESH4 tally in MCNP6.2?

Yes, TR and TRCL can be used to translate an F4 or FMESH4 tally in MCNP6.2. For F4 tally, which is a fixed-point detector tally, the transformation affects the location of the tally points. For FMESH4, which is a mesh tally, the entire mesh grid can be translated or rotated according to the specifications in the TR or TRCL cards. This feature is particularly useful for analyzing the effects of moving detectors or sources within a modeled environment.

3. How do you apply TR or TRCL transformations to an F4 or FMESH4 tally in MCNP6.2?

To apply TR or TRCL transformations to an F4 or FMESH4 tally, you need to define the transformation using the TR or TRCL card and then reference this transformation in your tally definition. For an F4 tally, you would specify the transformation in the tally definition line with the appropriate TR or TRCL number. For an FMESH4 tally, you incorporate the transformation number in the FMESH card. This links the defined transformation to the tally, applying the specified translation or rotation.

4. What are the limitations of using TR or TRCL with F4 or FMESH4 tallies in MCNP6.2?

While TR and TRCL transformations are powerful tools, they have limitations. For instance, complex rotations or translations might lead to errors in the positioning if not defined accurately. Additionally, excessive use of transformations can complicate the model, potentially leading to longer computation times and difficulties in debugging. It is essential to verify the transformed tally positions to ensure they are correctly implemented within the simulation geometry.

5. Are there any best practices for using TR or TRCL transformations with F4 or FMESH4 tallies in MCNP6.2?

Best practices for using TR or TRCL transformations with F4 or FMESH4 tallies include thoroughly planning and reviewing the transformation geometry before implementation to avoid errors. It is also recommended to keep the transformation definitions as simple as possible and to use visualization tools to confirm the placement and orientation of transformed tallies. Additionally, documenting each transformation clearly in the input file can aid in maintaining clarity and ease troubleshooting and reviews by peers or during audits.

Similar threads

Replies
2
Views
1K
Replies
10
Views
2K
  • Nuclear Engineering
Replies
1
Views
1K
  • Nuclear Engineering
Replies
2
Views
1K
  • Nuclear Engineering
Replies
1
Views
1K
  • Nuclear Engineering
Replies
1
Views
3K
  • Nuclear Engineering
Replies
2
Views
2K
  • Special and General Relativity
2
Replies
42
Views
4K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
2K
  • Programming and Computer Science
Replies
1
Views
1K
Back
Top