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Elizabeth Vega
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When I run the application, I get an error message. Fatal error electron importances are zero, I can't find what's wrong in the code.
Thaks for your comment...it was very helpfulTom.G said:Try looking at Section 2.9 in the this Users Manual.
TechReport_2017_LANL_LA-UR-17-29981_WernerArmstrongEtAl.pdf
(above found with:
https://www.google.com/search?hl=en&q=MCNPX+"electron+importance")
Line 124 in your attachment sets it to Zero.
Cheers,
Tom
This error typically occurs in the MCNPX (Monte Carlo N-Particle eXtended) simulation tool when the importance values for electrons in a certain region or cell are set to zero. Importance values in MCNPX are used to guide the simulation's particle tracking by altering the probability of particle survival. A zero importance effectively means that no electrons are expected to contribute to the simulation results in that region, which can halt the simulation if electrons enter these areas.
To resolve this error, you need to check and adjust the importance values assigned to electrons in your input file. Make sure that all regions where electrons might travel have non-zero importance values. You can set these values in the cells or surfaces definitions in your MCNPX input file. Reviewing the geometry and logic of your setup can help ensure that all importance assignments are correct and logical.
MCNPX uses importance values as part of its variance reduction techniques to efficiently simulate particle transport by influencing the probability of particle survival and tracking. Non-zero importance values for electrons (or any particle) ensure that the simulation accurately models particle interactions and transport within the specified regions. Zero importance values can mislead the simulation into disregarding significant physics or artificially terminating particle tracks prematurely.
Yes, setting the electron importance to a very low but non-zero value is possible and sometimes necessary, especially in regions where electron contribution to the simulation results is minimal but still non-negligible. This approach allows electrons to be tracked with reduced statistical weight, which can help in maintaining computational efficiency while still capturing necessary interaction data.
If adjusting the electron importance values does not resolve the issue, it's advisable to further investigate other aspects of your simulation setup. Check for possible errors in geometry definitions, material assignments, or boundary conditions. Also, ensure that your source definition and particle type settings are correctly specified. Consulting the MCNPX user manual or seeking advice from other experienced users through forums or professional networks can also provide additional insights and solutions.