Solving the 10 Particle Loss Problem After MCNP5 Run

[Rowayda]

After running MCNP5, the output run terminated because 10 particles got lost
how i can fix this problem ?

 

[DEvens]

The most likely thing is you have a problem in your geometry. Someplace you have a volume that is not part of a cell. Read your output file. Also, look in the user manual to see how to get it to output the track information for particles. What you want to find out is where a particle was when it got lost. That should give you a clue as to where there is a problem in your geometry. Every volume must be in a defined cell. You must not have any volume that is undefined. Also, every volume must be in exactly one cell. You can't have any volumes that are in two or more cells.

A frequent place to get into trouble is in arrays. You may not have defined the unit cell the way you thought. So it may not fill the volume you thought.

Another place to get in trouble is when you are doing a cell and the complement. You may have defined the outside of a cell differently from how you thought.

Look for places where you have unusual or irregular shapes, especially where they bound other irregular shapes.

Use the vised editor to help you figure out what cells are not properly defined. One of the tell-tales that vised shows is a dotted line at the boundary of a cell. That usually indicates a problem in the geometry.

 

[raining Pete]

There could be several reasons why the particles got lost during your MCNP5 run. Some possible solutions to fix this problem are:

1. Check your input file: Make sure that all the necessary parameters and inputs are correctly specified in your input file. Sometimes, small errors in the input file can cause particles to get lost.

2. Increase the number of particles: If the number of particles is too low, it is possible that some particles may get lost during the run. Try increasing the number of particles and see if the problem persists.

3. Adjust the geometry: If the geometry of your simulation is complex, it could be causing particles to get lost. Try simplifying the geometry or using more efficient tally options to reduce the number of lost particles.

4. Check the boundary conditions: Make sure that the boundary conditions are properly set in your input file. If the particles are escaping from the boundaries, it could result in lost particles.

5. Use a different random number seed: Sometimes, using a different random number seed can help in reducing the number of lost particles. You can try running the simulation with different seeds and see if it makes a difference.

If none of these solutions work, it is recommended to seek help from the MCNP5 user community or the software developers for further assistance.