In GSI's Program Advisory Committees external reviewers as internationally recognised experts in their fields give advice to the Directorate on selecting experiment proposals to grant beamtime.

General Program Advisory Committee (G-PAC) - an international program advisory committee of GSI, evaluating experiment proposals in the fields of nuclear and atomic physics. This General PAC also acts as umbrella for the different sub-PACs like:

Biophysics & Radio-Biology Program Advisory Committee (Bio-PAC) - evaluates experiment proposals in the areas of biophysics and radio-biology.

Materials Research Program Advisory Committee (Mat-PAC) - evaluates experiment proposals in the area of materials research.

PHELIX and Plasmaphysics Program Advisory Committee (PPAC, former PHELIX Committee) - evaluates experiment proposals concerning plasmaphysics and Petawatt High-Energy Laser for Heavy Ion Experiments (PHELIX).

Information for Users on services and beam time can be found on the Users' Webpages.