I'm looking to create a population model for the specific nuclides in a neutron spallation source. The source is a target (Tantalum clad Tungsten) which is being bombarded with protons, and in turn is producing neutrons. The change in a specific population of a Nuclide is going to be dependent on the initial population, the half life of the specific isotope, the isotopes which decay into it, and other factors.

Have models like this been made before, and are there any publications on the matter which anyone knows of?


1 Answer 1


These sorts of calculations are part of the design process for spallation sources and are done quite carefully. The tool of choice is MCNP, which has been extensively benchmarked over many decades. MCNP is maintained by folks at LANL, which happens to have a tantalum-clad tungsten spallation target; if you are on-site at LANL you should invite someone from that team to lunch and see if they can steer you in the right direction.

You should also look for papers (and their authors, who also like to eat lunch) describing the SNS mercury spallation target. Since the SNS is so much younger than LANSCE, the design computations were much more sophisticated. Likewise the ESS will have a helium-cooled tungsten target and is actively being designed at present.

  • $\begingroup$ are you angling for lunch? Just kidding... I second MCNP. You could set up the equations yourself, but would likely forget some isotope or another... $\endgroup$
    – Jon Custer
    Sep 24, 2015 at 16:02

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