Nuclear Data File Selection

[BV96 (David Breitenmoser)]

Dear FLUKA experts

The background of my two questions is a benchmark comparison between the MCNP6.2 and the FLUKA4.1.1 code for photoelectric simulations using radioactive sources (I’m using the raddecay and Hi-PROPErt cards in FLUKA):

1. Is it possible in FLUKA simulations to determine the cross-section, radioactive decay as well as particle emission data files, which have been used by default in a FLUKA simulation? In the paper from 2015 (Overview of the FLUKA code - ScienceDirect), it’s stated that EPDL97 is used for the photon cross section library. Is this still valid for the version 4.1.1.? Regarding the radioactive decay data, I found only a small reference in one of the CERN course materials, that NNDC data (I guess ENDF/B VII or VIII) together with other data (I guess JEFF and TENDL) is used. Does any body now, which versions of the corresponding databasis are implemented in the current FLUKA version 4.1.1? For your information: I would be especially interested in the nuclides Ba-133, Eu-152, Co-60, Cs-137 and Am-241.

2. Is it possible in FLUKA, to select a desired nuclear data file to be used in a specific simulation, e.g. ENDF/B-VIII for the simulation of a Ba-133 source?

Thank you so much for your support
Best,

David

[cesc (Francesc Salvat Pujol)]

Dear David,

Thanks for your post.

1 - Indeed, EPDL97 remains the source for photon interaction cross sections in FLUKA-4.1.1.

The decay database dates back roughly to the early 90s (i.e. ~30 years ago), and is consistent with Nuclear Data Sheets evaluations of that period. For your convenience, here are the employed half-lives for the isotopes you are interested in, along with the original reference:

• 60Co: 5.2714 y, as per https://reader.elsevier.com/reader/sd/pii/S0090375286801107
• 133Ba: 10.52 y, as per https://reader.elsevier.com/reader/sd/pii/0090375286800072
• 137Cs: 30.1 y, as per Nuclear Data Sheets for A=137 - ScienceDirect
• 152Eu: 13.542 y, as per https://reader.elsevier.com/reader/sd/pii/S0090375289800183
• 241Am: 432.7 y, as per https://reader.elsevier.com/reader/sd/pii/S0090375285800612

Evaluated nuclear data has of course evolved along the decades (adding further isotopes and refining others, the latter changes affecting mostly the last significant figures). Work is now underway on our side towards an updated version of the nuclear database to be released in the foreseeable future.

2 - No, unfortunately it is not possible/foreseen to feed in custom nuclear data files in FLUKA.

Hoping this helps somewhat,

Cesc