The discussion centers around the meaning and implications of setting neutron importance (imp:n) to 0 in MCNP, particularly in relation to tally results and computational efficiency. Participants explore the concept of importance in the context of neutron tracking, especially in void cells and shielding scenarios.
Participants generally agree on the role of neutron importance in computational efficiency but express differing views on the implications of using imp:n=0 versus imp:n=1 in specific scenarios, particularly regarding void cells and their boundaries.
The discussion highlights the importance of context in defining void cells and the potential consequences of neglecting neutron tracking in certain configurations, but does not resolve the nuances of these scenarios.
Individuals interested in computational modeling, particularly those using MCNP for neutron transport and criticality analysis, may find this discussion relevant.
Thanks, but if I do not care much about interactions, for example, I define a void cell, what is the difference between imp:n=1 and imp:n=0?QuantumPion said:Importance allows you to focus which particles you want to spend computational resources on. You can cease calculating interactions for particles that leave the problem area or give a higher importance to particles that make it through shielding. It is of primary importance in deep shielding applications since only a small percentage of particles will make it through the shielding, but you don't care about calculating the tracks of all the ones that don't make it through. Manipulating the importance let's you focus your computational power on the particles that do make it through without having to vastly increase the number of generations run.
seedsluis said:Thanks, but if I do not care much about interactions, for example, I define a void cell, what is the difference between imp:n=1 and imp:n=0?