Nuclear Structure Data Needs
Filip G. Kondev
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?
Collaborative meeting, Trento, May 28 –June 1, 2007
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 – cosmochronometers at the s-process path, but also many at the n-rich side
including the atomic (electron) environment?
2
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
Adopted
(best values)
Levels:
(E, J, T1/2, , Q,
configurations)
Gammas:
(Eg, BR, M,, ICC)
Decays
++

-n
etc.
www.nndc.bnl.gov/ensdf
Reactions
(HI,xng)
(p,p’)
(n, g), (n,xng)
Coul. Exc.
(,’), (,xng)
(d,p), etc.
3
Where to find the data - cont?
www.nndc.bnl.gov/ensdf
Atomic Masses
(Audi, Wapstra)
Nuclear Science
References (NSR)
Pros:
effort that already exists updated on regular basis
(NSDD Network under the
auspices of IAEA)
ALL experimental NS data for
ALL nuclei
ENSDF
IE
NuBase
RIPL
NuDat2
ENDF/JENDL/JEFF
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
4
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
5
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
?
6
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)
7
Bookkeeping
ansd_exp(theo).comments
experimental data
theoretical data
ansd_exp.dat
ansd_theo.dat
ansd.data (ascii file)
A N Z E
E/T
T1/2
0/1
77 38 39 0.0 0
E/T
0/1
63 MS 12
0
merge
ansd_merge.f (c; cpp)
ANSDM
ansd.comments
Decay Mode
E/T Delayed Particle Emission E/T
%- %+%+ % 0/1
0
100 %
0
0
%n
0
%p
10 % 1
%
0/1
2.2 % 0.5
0
8
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
9
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
10
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 -decay strength
distributions – from decay schemes & TAGS?
2
T 
const
2
|
M
|
 ij f
0 E Q
S  ( E f )  M if
I  (E)
1
S (E) 

f (Q - E , Z )T1 2 ft
11