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NNDC Databases: NuDat | NSR | XUNDL | ENSDF | MIRD | ENDF | CSISRS | CINDA |
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Chart of Nuclides DescriptionThe Chart of Nuclides is a software product that allows to search and plot nuclear structure and nuclear decay data interactively. The Chart of Nuclides was developed by the National Nuclear Data Center (NNDC) in Brookhaven National Laboratory. It provides an interface between web users and several databases containing nuclear structure, nuclear decay and some neutron-induced nuclear reaction information. Using the Chart of Nuclides, it is possible to search for nuclear level properties (energy, half-life, spin-parity), gamma-ray information (energy, intensity, multipolarity, coincidences), radiation information following nuclear decay (energy, intensity, dose), and neutron-induced reaction data from the BNL-325 book (thermal cross section and resonance integral). The information provided by the Chart of Nuclides can be seen in tables, level schemes and an interactive chart of nuclides. Searching the Chart of Nuclides There are three different search forms: one for levels and gammas, a second one for decay-related information, and a third one for searching the Nuclear Wallet Cards file. A description of the search capabilities can be found by clicking the help link at the top of each form, or by following the following links: We expect that most searches can be handled by the search forms provided; users with interests that can't be accomodated with these forms should not hesitate to contact us Glossary A brief explanation of the many terms used in the Chart of Nuclides can be found in this Glossary Chart of Nuclides contents The sections of the Chart of Nuclides related to levels, gammas and decay are obtained from the Evaluated Nuclear Structure Data File (ENSDF). Physicists from around the world have been contributing to this effort. The management of ENSDF resides at the NNDC. The Chart of Nuclides is periodically updated to reflect changes in ENSDF. A table with a brief statistics on the Chart of Nuclides can be found below:
A relational database is used to store the data. Structured Query Language (SQL) commands are issued to access the database. The Chart of Nuclides relies on Java to accomplish its programming tasks. Terms of use This disclaimer applies to all BNL web products, including the Chart of Nuclides. The Chart of Nuclides contains evaluated nuclear data, that is, recommended values following a careful analysis of the available data. We can not, however, guarantee the accuracy of the data or the absence of errors in the application. Users are urged to promptly report any problems encountered when using the Chart of Nuclides. User should be aware that the Chart of Nuclides contents change often as new data are incorporated.
Users should feel free to use the information from the Chart of Nuclides (tables and plots) in their work, reports,
presentations, articles and books.
For those interested in quoting the Chart of Nuclides, we suggest the use of the following citation format: National Nuclear Data Center, information extracted from the Chart of Nuclides database, http://www.nndc.bnl.gov/chart/ Interactive Chart of Nuclides Experimentally known nuclei are represented by a cell in a chart with the number of neutrons on the horizontal axis and the number of protons on the vertical axis.
The color of the cell is used to indicate the ground state half-life or the ground state predominant decay mode. It should be kept in mind, however, that there are nuclei with more than one decay mode, or having levels with a wide range of half-lives. This color scheme oversimplifies the description of a nucleus by choosing just one color. As a result, the chart should be only used as a visualization tool. It is advised to use the full list of levels for a complete information about decay modes and half-lives. The chart can be seen with 4 different zooming options. With the largest zoom value, the entire chart is displayed and the magic numbers 8, 20, 28, 50, 82 and 126 are indicated. For smaller zoom values, only a fraction of the chart is displayed; the nucleus at the center of the viewing window is marked with a magenta border; neutron ( horizontal axis ) and proton numbers ( vertical axis ) are indicated. When the zoom level is equal to 1, the name of the nucleus, the ground state half-life, the two decay modes with the highest probability and its natural abundance are displayed.
Ground and isomeric state information can be obtained by clicking on a given nucleus. This information is displayed under the chart of nuclides. Links to a list of levels, a level scheme, and decay radiation information are provided when available. Unless the zoom is at the largest value, clicking on a given nucleus also re-centers the chart. Further navigation possibilities can be obtained by using the arrows on the right-top corner of the window, as well as the 'Nucleus' textbox under the zoom control. In order to optimize the transfer of information when using the interactive chart of nuclides, pop-up boxes (tooltips) containing level information have been implemented. The tooltips are triggered when the mouse is over a given nucleus on the chart. Javascripts with image mapping are used to produce this effect. An example can be seen in the figure below.
Slow computers and slow internet browsers will be challenged by the tooltips, specially at the largest zoom. Users can choose to turn the tooltips feature off using the control menu on the right side in the main page. Fast browsers, such as Mozilla Firefox, respond well on slow computers and internet connections. Finally, it is recommended to view the chart with a monitor set at a resolution larger that 900 by 800 pixels and to use the latest versions of internet browsers. The uncertainty associated with a given quantity can be expressed in the so-called Nuclear Data Sheets style, or in a standard style. The Nuclear Data Sheets style has been used for a long time since it facilitates data storage, which was crucial in the early days. A table with a brief explanation of the Nuclear Data Sheet style is given below:
Level Schemes As mentioned before, a link to a web page with a levels plot is provided after clicking on a given nucleus. An example of it can be seen in the figure below:
The level scheme is rendered in a single image. Most nuclei, however, have complex level schemes that won't fit in just one image. As a consequence, only selected parts of the level scheme should be plotted at a time using the interactive features provided Levels are plotted in vertical groups; each band is assigned one such a group; levels that are not known to belong to a band, labeled as "Non-band levels", are also plotted in vertical groups. The way these non-band levels are plotted is based solely on energy-spacing considerations to avoid overwriting, that is, there is no physics behind how these levels are grouped in vertical structures; a change of image size or energy limits will likely modify the way these levels appear plotted. The first time the level scheme is plotted, all levels will be included. A form at the top of the plot can be used to replot with the following possibilities:
Levels with unknown value of absolute energy but with a known relative energy, for instance levels noted as X+500, are plotted at an arbitrarily choosen value of 200 keV from the ground state, i.e. X+500 will appear at 700 keV. Additionally, the neutron separation Energy (Sn) and the proton separation energy (Sp) are indicated in the level scheme. Please, don't hesitate to email your comments Back to the Chart of Nuclides Chart of Nuclides database manager and web programming: Alejandro A. Sonzogni, NNDC, Brookhaven National Laboratory (sonzogni@bnl.gov) |
