The Geant4 Collaboration is organized in the following 15 Working Groups, according to the main area of responsibility and reflecting, approximately, the categories - i.e. sub-domains and activities - identified in our project:
- Advanced Examples
- Documentation Management
- Electromagnetic Physics Processes
- Geometry and Transport
- Hadronic Physics Processes
- Generic Processes and Materials
- Novice and Extended Examples
- Particles and Tracking
- Physics Lists and Validation Tools
- Run, Event and Detector Responses
- Software Management
- Testing and Quality Assurance
- User and Category Interfaces
The Geant4 members contribute to one or more of these Working Groups, according to their expertise and interest.
At the beginning of each year, a census is carried out in each Working Group to know the contribution of each member in the previous year, and the pledged one for the current year, as well as the proposed plan of work for the year. The latter is then used to prepare the overall Geant4 plan of work of the year, which is presented and discussed with users in a dedicated Geant4 Technical Forum, usually held in the first quarter. The information on the committed effort of each Working Group - as the sum of each member contribution, taken as provided, with neither a minimum threshold, nor an auditing mechanism - is used to decide the number of representatives of each Working Group in the Geant4 Steering Board.
The coordinator and deputy coordinator (and eventual other representatives at the Steering Board) of each Working Group are elected every two years, with one vote for each Geant4 collaborator and member of a Working Group. The candidates who receive the highest number of votes should then be approved and appointed by the Steering Board. The rationale behind this procedure is to ensure that both technical and physics-related choices concerning Geant4 are taken by active developers who are trusted by a majority of their colleagues.
The main duties of each Working Group coordinator are the following:
- Carry out the census of the Working Group at the beginning of the year;
- Preparing the plan of work of the year of the Working Group;
- Monitor throughout the year the progress in the implementation of the plan of work;
- Organize regular meetings of the Working Group, as well as relevant special meetings or dedicated workshops between developers, and sometimes also with users;
- Follow issues, problems, bugs and new requirements which are under the responsibility of the Working Group.
A Task Force, and its members, can be set-up by the Steering Board to execute an important task for Geant4, involving several Working Groups.
The chair of a Task Force is nominated by the Steering Board.
Often a Task Force has a limited duration, e.g. a few years ago there was a Task Force dedicated to the achievement of the Multi-Threaded capability of Geant4; a more recent example, still existing, is the Task Force dedicated to prepare a new web site for Geant4. There are also permanent Task Forces, such as the one on Physics Validation, and the more recent one on R&D simulation activities.