Livechart Data Download API
This API allows the direct download of data. At the moment the format provided is CSV (comma separated values). Future developments will include more formats, and more options to build custom queries.

The service URL is followed by request parameters.
(please note that using 'v0' is the same as using 'v1' )
Here some examples of data request parameters:
fields=levels&nuclides=135xe    try it »
Xe-135 levels
fields=gammas&nuclides=135xe    try it »
Xe-135 gamma transitions
fields=ground_states&nuclides=all    try it »
all ground states in the database
fields=cumulative_fy&parents=233u    try it »
U-233 cumulative fission yields
fields=cumulative_fy&products=135xe    try it »
cumulative fission yields producing Xe-135
fields=decay_rads&nuclides=135xe&rad_types=e    try it »
electrons (Auger and conversion) from Xe-135 decays
fields=bin_beta&nuclides=135xe&rad_types=bm    try it »
Beta and (anti)neutrino energy distributions from Xe-135 G.S. decays

Jupyter lab
The Livechart API works very effectively with Python data analysis libraries (pandas and plotly in these examples), the first step to build models for Machine Learning.
Many examples, including 3D plotting, are detailed in this Notebook

There have been cases in which the service returns an HTTP Error 403: Forbidden
The workaround is to add an user agent to the request.
In Python:
def lc_read_csv(url):
    req = urllib.request.Request(url)
        'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:77.0) Gecko/20100101 Firefox/77.0')
    content = urllib.request.urlopen(req)
    return content

in Java:
protected String lc_read_csv(url){

    URL murl = new URL(url);
    URLConnection conn = murl.openConnection();
    "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:77.0) Gecko/20100101 Firefox/77.0");
    BufferedReader br = new BufferedReader(
                   new InputStreamReader(conn.getInputStream()));

    String inputLine;
    StringBuffer sb = new StringBuffer();
    while ((inputLine = br.readLine()) != null) {
    return sb.toString();

For other languages, add the suggested user agent to the request using the avaliable function
API description
Service URL
The URL of the service is followed by a chain of parameters linked by &. A parameter is specified as name=value




Specifies which fields are fetched. At the moment, a predefined group of fields is avaliable. Further development will allow the user to specify the list of fields.

ground_states or levels or gammas or decay_rads or cumulative_fy or independent_fy or bin_beta


See below for the description of the fields included in each group.


Is mandatory for ground_states, levels, gammas, decay_rads, and bin_beta
It has no effect on cumulative_fy or independent_fy

Restricts the retrieval to the specified nuclide
In this version of the API, only one nuclide can be specified

nuclides=135xe (mass+element)
nuclides=all allowed only for ground_states. All ground states are returned


Valid only for cumulative_fy and independent_fy

All the products for the specified parent are returned.
In this API version only one parent can be specified

parents= 232th or 233u or 235u or 238u or 237np or 239pu or 241pu or 241am


Valid only for cumulative_fy and independent_fy

All the fission yields of this product, for any parent, are returned
In this API version only one product can be specified

products=135xe (mass+element)


Only for, and mandatory for, decay_rads, and bin_beta
Only one value is allowed

Data are returned only for the specified type of radiation
In this API version only one radiation can be specified

Values for decay_rads
a bp bm g e x (α, β-, β+, γ, Auger and conversion electron, X-ray)

Values for bin_beta
bp bm ( β-, β+)

Full Example


Only for bin_beta
Only one value is allowed
Optional, specifies the sequential number for an excited state

1 2 3 ... (first metastable state, second, third, ... )

Full Example
fields=bin_beta&nuclides=135xe&rad_types=bm metastable_seqno=1
This would retrieve the spectra for the decay of the 526.5 keV level of Xe-135

Fields content
Data sources
In the following
Half-life uncertainity is given in ENSDF notation, referring to the significant digits.
For example 12.1 h 11 means 12.1 h ± 1.1 and 12.1 h 1 means 12.1 h ± 0.1
The Uncertainity of the Half-life in seconds is symmetrised
Field groups
ENSDF_publication_cut-off, ENSDF_authors, and extraction date are at the end of each row
Properties on the nuclide and its ground state level
Properties of the excited energy levels of a nuclide
The meaning and source of the fields are the same as the ground_state set. Additional fields are:
Properties of the electromagnetic transitions between energy levels of the nuclide
In the following :
Properties of the radiations emitted by the daughter(s) of the nuclide that decays
In the following : Fields common to all decay radiation types

α radiations

• X-ray, electrons

• β radiations

• γ radiations

β+/- and ν / anti ν spectra

Spectra are obtained using Betashape code

Error codes

When no data are retrieved, a numeric code is returned

Please address any feedback to NDS contact point

IAEA - Nuclear Data Section
Vienna International Centre, PO Box 100
A-1400 Vienna, Austria
Telephone: (+431) 2600-0
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