# Nuclear Data Generation – pyne.dbgen¶

Pyne provides an easy-to-use, repeatable aggregation utility for nuclear data. This command line utility is called nuc_data_make builds and installs an HDF5 file named nuc_data.h5 to the current PyNE install. Nuclear data is gathered from a vareity of sources, including the web and the data files for other programs installed on your system (such as MCNP).

All of the code to produce the nuc_data.h5 file is found in the dbgen sub-package. This package was designed to be modular. Therfore nuc_data_make may be run such that only an available subset of nuc_data.h5 is produced.

As this is the library refence portion of the documention, the underlying functionality for each module is displayed rather than how to use the end product. However, most modules here are divided conceptually into three parts, run in series:

1. Gather raw data and place it in a build directory.
2. Parse the raw data and put it in a form suitable for storage in nuc_data.h5.
3. Write the parsed data to nuc_data.h5.

Database Generation Modules

The PyNE development team would like to thank the following people and organizations for allowing us to redistribute open nuclear data in binary form as part of nuc_data_make.

## Prebuilt Nuclear Data¶

For developers who wish to generate the open nuclear data file that is distributed along with PyNE, please run the following command:

nuc_data_make --fetch-prebuilt False --make-open-only True -o prebuilt_nuc_data.h5