1. The search engine¶
Data are stored in a SQLite database, and normally users do not need direct access to it, and do not use SQL language to retrieve the data.
Description and schema of the database are presented here
2. Underlying databases¶
The main source is the ENSDF database (Evaluated Nuclear Structure Data Files), it is the only database that covers the entire chart of nuclides. It is produced by the International Network of Nuclear Structure and Decay Data Evaluators (NSDD), under the auspices of the IAEA
The National Nuclear Data Center at Brookhaven National Laboratory (NNDC) is responsible for coordinating the evaluation effort and for hosting the database.
NDLab database incorporates the ENSDF-derived RIPL - Discrete Levels segment database, to which has been added a complete description of levels and gamma transitions
A relevant new feature of the NDLab database is the relational link between levels and gammas in the ENSDF decay datasets and their counterpart in the adopted datasets.
Levels and gamma transitions¶
The RIPL database is derived from the ENSDF database, with contribution from NUBASE and AME databases. NUBASE is used to fix some of the unknown level energies, expressed in the ENSDF in terms of “0+X”, or “238+X” , etc… where X is an unknown energy.
RIPL also provides, in many cases, a unique value for spin when the ENSDF assignment is non-unique or unknown. As already said, this is only an additional field that users should take cum grano salis; the original ENSDF assignment is present in the database and should be used for accurate structure and decay description
The RIPL Discrete Levels database is described in:
Linking Adopted and Decay datasets¶
For a given nuclide, the ENSDF database places the evaluated levels and gamma transitions properties in the “Adopted”, which are derived by making an overall fit of various “Decay” (and “Reaction”) datasets.
It can happen that the same level, or the same gamma, is present in more than one of these datasets with, for example, an energy slightly different in each occurrence.
With data scattered in various datasets, and with no easy linking between them, it becames difficult for users to navigate the data.
Take the following Sm-152 gamma transition as example:
Gamma Start level End level Dataset
energy energy energy
119.46 1082.842 963.358 Adopted Sm-152
118.97 1082.816 963.363 Decay Eu-152 to Sm-152
119.44 1082.88 963.40 Decay Eu-152-m to Sm-152
119.5 1082.77 963.25 Decay Pm-152 to Sm-152
....
The NDlab database links each gamma and each level in the “Decay” dataset to the “Adopted” one, removing the multiple, but different, occurrences of a same entity.
Attention
Please note that for accurate structure and decay description, one should revert back to the ENSDF original datasets
3. Data sources¶
When not otherwise stated, data are from the ENSDF database
Masses and Q-values: AME2020, published in Chinese Phys. C 45, 030002 (2021) and Chinese Phys. C 45, 030003 (2021)
Abundances: NUBASE2020 published in Chinese Phys. C 45, 030001 (2021).
Fission Yields: Joint Evaluated Fission and Fusion File (JEFF) 3.1.1
Charge Radii: I.Angeli, K.P. Marinova, Atomic Data and Nuclear Data Tables 99 (2013) 69-95 DOI:10.1016/j.adt.2011.12.006
Atomic radiations calculated following: E.Schönfeld, H.Janßen and its references.