EGSnrc is a software toolkit to perform Monte Carlo simulation of ionizing radiation transport through matter. It models the propagation of photons, electrons and positrons with kinetic energies between 1 keV and 10 GeV, in homogeneous materials. EGSnrc is an extended and improved version of the Electron Gamma Shower (EGS) software package originally developed at the Stanford Linear Accelerator Center (SLAC) in the 1970s. Most notably, it incorporates significant refinements in charged particle transport, better low energy cross sections, and the egs++ class library to model elaborate geometries and particle sources.

EGSnrc is distributed as free software under the terms of the GNU Affero General Public Licence. Please review the LICENSE document before downloading the software. In practice, this licence imposes no restriction on using EGSnrc. However, if you want to further convey verbatim or modified versions of the code, or any work based on any EGSnrc component (including any such work operated remotely over a network), you must do so under the same licence terms. Contact us if you wish to licence EGSnrc under different terms.

EGSnrc can be installed on computers running Linux, OSX or Windows operating systems. As a general-purpose Monte Carlo toolkit, EGSnrc provides source code and utilities to build and run your own radiation transport simulation applications. To use EGSnrc on any platform you need:

• a Fortran compiler
• a C compiler
• a C++ compiler
• the GNU make utility
• the Tcl/Tk interpreter and widget toolkit
• the Grace plotting tool

Please read the [installation instructions] (https://github.com/nrc-cnrc/EGSnrc/wiki/Installation-overview) in the wiki for more details about these software components.

Installation involves downloading the EGSnrc source code, and then configuring EGSnrc for your computer. The recommended way to obtain the source code is to clone the EGSnrc repository on your computer using the git revision control software, via the SSH clone URL:

git clone git@github.com:nrc-cnrc/EGSnrc.git

Once you have downloaded the source code, you must run a configuration GUI or script to set up and compile EGSnrc software components for your computer. Please read the full [installation instructions] (https://github.com/nrc-cnrc/EGSnrc/wiki/Installation-overview) in the wiki for more details on how to download and configure EGSnrc.

The EGSnrc user manuals in PDF format can be downloaded from the releases page. Download the EGSnrc-manuals.zip archive, and unzip it. If you installed EGSnrc, you may want to move the extracted PDF files to the EGSnrc/HEN_HOUSE/doc directory for convenience.

Use the issue tracker to report bugs, inaccuracies or even small typos in the EGSnrc project files. The tracker lets you browse and search all documented issues, comment on open issues, and track their progress. Note that the issue tracker is not meant for technical support; open an issue only if it pertains to an error condition which is precise and reproducible.

Please contribute to the EGSnrc project by implementing new features, creating new data sets, correcting errors, and improving documentation. You can submit small corrections and contributions as issues in the issue tracker. For more extensive contributions, familiarize yourself with git and github, work on your own EGSnrc project fork and submit your changes via a pull request. Note that significant additions will require a transfer of copyright to the National Research Council of Canada before they can be merged into the EGSnrc distribution.