TAGS data in ENDF/B-VII.1 and

ENDF/B-VII.1.1A.A. Sonzogni, T.D. Johnson, E.A. McCutchan,

National Nuclear Data Center

IAEA Consultant meeting 2014 #2 - Alejandro Sonzogni

Outline

TAGS Decay Data in ENDF/B-VII.1

Updates in ENDF/B-VII.1.1

Recent work on Antineutrino spectra calculations

Searching for systematics

IAEA Consultant meeting 2014 #3 - Alejandro Sonzogni

ENDF/B-VII.1

EEM and ELP data for most of Greenwood nuclides and all of the Valencia results. There is an inconsistency since EEM is not equal to <Eg> and ELP not equal to <Eb->. It also includes CGM calculations, with the latest Q-values, for nuclides with incomplete data in ENSDF.

ENDF/B-VII.1.1 (in progress)

Contains Ib from Greenwood and Valencia TAGS.Contains Ib from a fit to Rudstam/Tengblad data.Ib (gs) for 92Rb set to 95.1%

IAEA Consultant meeting 2014 #4 - Alejandro Sonzogni

Recent work on Antineutrino Spectra Calculations

Antineutrino spectra are calculated as (Vogel 1981)

Spectrum = S CFYi Spectrumi

Cumulative Fission Yields from JEFF-3.1

No adjustable parameters

IAEA Consultant meeting 2014 #5 - Alejandro Sonzogni

Nuclides with CGM calculations contribute about 4% to 12% of the total spectra.

Recent work on Antineutrino Spectra Calculations

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Recent work on Antineutrino Spectra Calculations

Comparison with Rudstam data for the two most important nuclides for energies higher than 5 MeV, assuming allowed shape.

New measurements are needed to test deviation from allowed shapes for first forbidden transitions.

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Antineutrino multiplicities

The integral of antineutrino multiplicity follows a systematics similar to delayed nu-bar.

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Due to incomplete decay schemes and not very precise fission yields, the summation method can’t be used to calculate antineutrino spectra with high-precision.

Odd-Z, Odd-N nuclides are the main contributors to the antineutrino spectra, due to a) large Qb and existence of low-spin ground state/isomer.

Similarly, the light fission fragment contributes more antineutrinos than the heavy group.

Some conclusions

IAEA Consultant meeting 2014 #9 - Alejandro Sonzogni

Searching for systematicsThe basic parameters in beta decay are:Z and N of the parent nucleusHalf-lifeQ-valueSpin and parity of parentIb(Elevel)

From Ib we can derive:

EEM: Average level energyLevel SD: Standard deviation on EEM

EEM = S Ib Elevel

Level SD = ( S Ib (Elevel – EEM)2 )1/2

IAEA Consultant meeting 2014 #10 - Alejandro Sonzogni

In the past, T1/2 was related to Qb using the Kratz-Hermann Systematic: T1/2=a(Qb-C)b

The data are from complete ENSDF decay datasets

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Some general observations:

a) Even-Even nuclides have smaller values of level SD and align better on the KH plot.

b) Odd-Odd are far more spread.

c) Is C the best parameter? If Level SD is small, EEM would be a better one.

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J >= 2

J < 2 J < 2

J >= 2

130Sn (7-)

182Hf (8-)

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Even if Level SD is smaller than 0.5 MeV, we still get large scatter in non EE nuclei

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Even-even nuclides seem to group rather nicely, with the exception of 130Sn (7-) and 6He that has a log ft=2.9. Full symbols are the TAGS data.

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Since l is the first moment of the Ib distribution, and EEM is the 2nd order moment , is there a EEM / T1/2 correlation

IAEA Consultant meeting 2014 #17 - Alejandro Sonzogni

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Some general comments

Fission yields are needed in summation and decay heat calculations. However, there are discrepancies between the different libraries, see http://www.nndc.bnl.gov/nudat2/fyields/

In particular, for 92Rb a measurement from Lowell puts the CFY at around 7%.

Shape of 1st forbidden non-unique transitions could explain the Daya Bay shape problem. New precise measurements are needed.

We had not luck with PACs in the US, even our recent article received some ‘interesting’ comments from the referee, as there are too many nuclides contributing to make it worth an experimental campaign. Do we need another Subgroup 25?