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Nuclear Structure Data Needs

Nuclear Structure Data Needs. kondev@anl.gov. Outline. What kind of nuclear structure and decay data are needed – an incomplete list Where to find the relevant data?

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Nuclear Structure Data Needs

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  1. Nuclear Structure Data Needs kondev@anl.gov Outline • What kind of nuclear structure and decay data are needed – an incomplete list • Where to find the relevant data? • Suggestions on how to proceed in the future in order to update the corresponding nuclear astrophysics data libraries with the best available nuclear structure data? Filip G. Kondev Collaborative meeting, Trento, May 28 –June 1, 2007

  2. What NS data are needed? • Priority 1 – masses & decay data • masses, T1/2, decay modes & BR and delayed-particle emission probabilities • Priority 2 – level energies, quantum numbers, T1/2 of excited states, etc. • depends on the site of nucleosynthesis • s- and p-processes – near the valley of stability – a lot of data • rp-process – at the proton-rich side • r-process - at the neutron-rich side – much more data is expected in the future with the RIB facilities • important for model (cross-section) calculations – level densities, partition functions, etc. • important when we are dealing with isomers – cosmo-chronometers at the s-process path, but also many at the n-rich side including the atomic (electron) environment?

  3. Where to find the data – ENSDF? Effort within NSDD network, under auspices of IAEA. Database is managed by NNDC (BNL) Contents: Evaluated nuclear structure and decay data for all known nuclei, organized in over 260 mass chains ENSDF Reactions (HI,xn) (p,p’) (n, ), (n,xng) Coul. Exc. (,’), (a,xng) (d,p), etc. Adopted (best values) Levels: (E, J, T1/2, , Q, configurations) Gammas: (Eg, BR, M,, ICC) Decays - ++  -n etc. www.nndc.bnl.gov/ensdf

  4. Where to find the data - cont? NuDat2 IE Nuclear Science References (NSR) Atomic Masses (Audi, Wapstra) www.nndc.bnl.gov/ensdf • Pros: • effort that already exists - updated on regular basis • (NSDD Network under the auspices of IAEA) • ALL experimental NS data for ALL nuclei ENSDF RIPL ENDF/JENDL/JEFF NuBase • Cons: • updating time – vary between 6 to 10 years in some cases • not all data are relevant to the needs of the astrophysics community • “strange” format

  5. Where to find the data - cont? http://www.nucleide.org/DDEP_WG/DDEPdata.htm • Pros: • include comprehensive X-ray data • updated on regular basis • Cons: • decay data only • mostly for NE & metrology applications • relevant to a handful of s-(p-) process nuclei

  6. Where to find the data - cont? http://amdc.in2p3.fr/web/nubase_en.html • Pros: • based on ENSDF, but updated for recent data • Cons: • updating time – 5-8 years • no spectral information • continuity Atomic Masses Evaluations?

  7. What would be useful to have? • although ENSDF is the best source for a variety of experimental NS and decay data, effort is needed to (i) extract the needed data for astrophysics applications in user defined formats & (ii) to update for recent discoveries (~30 new isotopes/yr) • results from model calculations should be also included – for many nuclei, especially on the neutron-rich side, experimental data do not exist • in an “ideal case scenario” - a merge between experimental & theoretical data is needed – development of a dedicated Astrophysics Nuclear Structure Data (ANSD) module – easily included into Reaclib (or any other library)

  8. Bookkeeping ansd_exp(theo).comments experimental data ansd_exp.dat theoretical data ansd_theo.dat merge ansd_merge.f (c; cpp) ANSDM ansd.comments ansd.data (ascii file) A N Z E E/T T1/2 E/T Decay Mode E/T Delayed Particle Emission E/T 0/1 0/1 %b- %e+%b+ %a 0/1 %n %p %a 0/1 77 38 39 0.0 0 63 MS 12 0 0 100 % 0 0 0 10 % 1 2.2 % 0.5 0

  9. What I’d like to propose? • ANL in collaboration with JINA and other interested groups can provide the Astrophysics Nuclear Structure Data (ANSD) module: • updates will be provided regularly – once a year • data will be peer-reviewed by expert(s) in the field • the ANSD module will be a merge between experiment & theory - it will include available experimental data for all known nuclei, together with predictions for those not yet known • the corresponding codes used to merge (manipulate) the experimental & theoretical data sets will be provided, together with subroutines that can read the corresponding data files

  10. What would be the benefits? • Comprehensive & Complete: • All related quantities will be provided, together with estimates of their uncertainties • Reliable: • Data will be correctly represented • Up-to-Date: • Consequences of new measurements will appear promptly – regular updates will be provided • Accessible: • Data will be available in an user-defined format • You will have all that for FREE:sorry no charges

  11. What about other data? Priority 2:level energies, quantum numbers, T1/2 of excited states, etc. – the needs for dedicated effort should be driven by the users and modelers – many of those can be find in ENSDF – if there is a need we can provide it Priority 1: usually a comparison between experimental and theoretical T1/2 is used to test the reliability of a particular model - what about the b-decay strength distributions – from decay schemes & TAGS?

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