Alejandro Sonzogni NSDD 2007

Decay Data LibraryIn ENDF/B-VII

Alejandro Sonzogni

National Nuclear Data CenterBrookhaven National Laboratory

E-mail: sonzogni@bnl.gov

Brookhaven Science Associates

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ENDF/B-VII.0 Decay Data Sub-library Single file, divided in datasets

All numerical, ready to be used in complex decay networks (reactors, stars) where nuclear decay and energy release is calculated as function of time.

A single dataset per ground state / isomer including all possible decays. Total of 3838 datasets in new sub-library. Previous version had 979 datasets (ENSDF 1985) mainly by Charlie Reich.

Work started in 2004 and was finished in December 2006.

Mostly derived from ENSDF, 2005 Nuclear Wallet Cards, with additional data.

Dataset contents: Energy level, isomer count (0 for GS, 1 for first isomer,…) Branching ratios to daughter nuclide/s isomer counts Half-life, spin and parity, mass Average radiation energies Discreet radiation energies and intensities

In the ENSDF to ENDF translation: Sometimes we need to add ENSDF datasets, ex 112In, EC=56% and B-=44% Sometimes we need to subtract, ex 137Cs – 137Ba, 661 belongs to 137BA IT decay Translate all strings to numbers.

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T1/2, %-n from Pfeiffer, Kratz, Moller (2002)

1 ms to 1 s

Partial T1/2 information

No Decay information other than Q-value

Use of new Internal Conversion Coefficients (BRICC) Better <ECE>

<E> from SPEBETA for 2nd forbidden non-unique transitions

44 days < T1/2 < 1x107 years

TAGS (Total Absorption Gamma Spectrometer)10 s < T1/2 < 2000 s, Qdecay> 4 MeV

Incomplete Decay Scheme<E> and <E-> from integral measurement

48 materials from INEL + 2 ISOLDE/JyvaskylaSubject of WPEC Subgroup 25

ENDF/B-VII.0 Decay Data Sub-library

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ENDF/B-VII.0 Decay Data Sub-libraryAuthorship information is carried throughout the sub-library

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Decay Heat

Decay Heat(t)= i Ni(t) Ei

Ei: Energy released in decay, sum over all nuclear species involved in the decay, 732 fission products for a total of 1000 including the daughters

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Delayed Neutrons

d(thermal)=0.0159/fission

(using ENDF/B-VII.0 decay data library and JEFF-3.1 fission yields)

Very close to Keepin and JEFF-3.1 time dependence

ENDF/B-VII.0:

d(thermal)=0.01585/fission

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Delayed Neutrons

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Summary

New decay library as part of ENDF/B-VII.0

Much larger coverage, many more precise values of half-life, energy and intensity. Derived from the latest ENSDF files.

Inclusion of TAGS data and better treatment of long-lived beta emitters.

Validated with Decay Heat and Delayed Neutron calculations.

Sensitivity study to obtain list of priority nuclides, feedback to experimenters.