FAQs (KNC)

From NucleonicaWiki
Jump to: navigation, search

Contents

Frequently Asked Questions (FAQ)

What is the difference between the Karlsruhe Nuclide Chart and the Nuclide Explorer in Nucleonica?

The Nucleonica Team manages both the Karlsruhe Nuclide Chart project and the nuclear science web portal Nucleonica.


Pu239 in the Karlsruhe Nuclide Chart

The Karlsruhe Nuclide Chart is currently only available in paper versions. It contains concise information on experimentally observed nuclides from the latest scientific publications (Nuclear Data Sheets, XUNDL, Nuclear Science References and recent journal publications). However, the information in the paper-based Chart is limited to the half-lives, decay modes, branching ratios (qualitatively) and energies of the most important radiations. For Pu239, for example, there is only one (weak) gamma energy listed (see image).


Pu239 data in Nucleonica

In Nucleonica's applications (see some examples below), a complete datafile is required for example for dosimetry and shielding calculations. The datafile used in Nucleonica is based on the OECD NEA JEFF3.1 datafile. The main advantage of JEFF3.1 is that the spectral data are complete (for Pu239 there are over 200 gamma energies and emission probabilities, in the Karlsruhe Nuclide Chart there is only one (weak) gamma energy listed). The main disadvantage is that JEFF3.1 is only updated every few years. It also contains information on nuclides which have not yet been identified experimentally.

The Nuclide Explorer (JEFF3.1 data)
Universal Nuclide Chart with animations (JEFF3.1 data)
Nuclear Data Retrieval (JEFF3.1 data)

Why is the Karlsruhe Nuclide Chart so popular?

(Qu.) In the literature one can find many collections of nuclear data: ICRP 38 (1983), IAEA Safety Series 115 (1996), Guideline 96/29/Euratom (1996), K. Debertin (PTB) in Kohlrausch "Praktische Physik" Band 3 (1996), "Handbook of Health Physics and Radiological Health", 3. edition (1998), IAEA Safety Guide TS-G-1.1 (June 2002), Schultz/Vogt "Grundzüge des praktischen Strahlenschutzes", 3. edition (2004), ...... In addition there is much information available on the internet.

So why is the Karlsruhe Nuclide Chart so popular?

(Ans.)

1. In contrast to many other data sources, the Karlsruhe Nuclide Chart (KNC) is based primarily on EXPERIMENTAL data. Currently experimental data on 2962 ground states and 692 isomers is given.

2. The data given in the KNC is COMPREHENSIVE. Data on all new nuclides (e.g. new super heavies, nuclides at the proton and neutron driplines, etc.), half-lives, energy emissions etc. are given. This is not the case in many datafiles. The European Datafile JEFF3.1, is a very good example of this. JEFF stands for Joint Evalauted Fission and Fusion file. It has been developed mainly for the nuclear reactor community. New nuclides with very short half-lives are not of interest here and are in many cases just omitted. Also new modes of decay are not listed here. Examples here are cluster emission and bound beta decay. This latter process is of great interest in astrophysics - but it is not of interest in JEFF.

3. The data given in the KNC are CONDENSED. Each nuclide in the KNC is descirbed in a small box wich contains the half-life, emission energies etc. Due to space, however, only very limited data can be given in such small boxes. This is both an advantage and a disadvantage. In moderrn electronic databases much more data is given but for most cases is it not particulary of interest. Consider Pu-239: in the Nucleonica electronic database, for example, there are over 200 gamma lines and emission probabilities listed (these lines are important for applications for example in dosimetry & shielding). So in the KNC, since the space is very limited, great care is taken to choose the most important data.

4. The KNC is of great didactic value. Once you have understood the basic colour schemes (yellow, red, blue etc.) you can trace out the decay scheme "by hand". This also holds true for nuclear reactions e.g. the buildup of actinides in a reactor.

5. The KNC "brochure" with fold-out chart is very popular. It is not uncommon to see people walking about with this brochure under their arm. It can be taken and read in trains, planes etc. It is just very convenient. Excerpts from this chart are included in school physics textbooks. The wallcharts hang on the walls of scientists and students all over the world.

To summarise:

The paper-based Karlsruhe Nulcide Chart, with its fold-out and wall chart versions, remains an aesthetically appleaing record of human achievement in nuclear science. It provides a unique overview of current knowledge and is for many the preferred medium for ease of use, convenience and practicality.

Why is Ta181m (half-life 6.8 µs) not in the Karlsruhe Nuclide Chart?

In the "Explanation of the Chart of the Nuclides", it is stated...

Metastable states, which do not undergo alpha, or ß-decay, or spontaneous fission, i.e. decay only by gamma emission, are included only if their half-life is larger than 1 s.

There are very many metastable states with short half-lives and which decay by gamma emission. For space reasons these have not been included in the present edition of the Karlsruhe Nuclide Chart. Due to the importance of some of these nuclides e.g. Ta181m, we are currently reconsidering this. If the metastable state undergoes decay by particle emission (rather than by gamma emission), they are indicated even if their half-lives are very short.

Personal tools
nucleonica premium
Karlsruhe Nuclide Chart