Welcome to the Gas Detectors Development Group (GDD)

Inventors of the Multi-Wire Proportional Chamber (MWPC) and the Gas Electron Multiplier (GEM)


  Created in the late sixties by Georges Charpak, inventor of the Multiwire Proportional Chamber and 1992 Nobel Laureate for Physics, the group has been active in the development and applications of advanced detectors for particle physics. After Charpak's retirement in the early nineties, the research was led by Fabio Sauli, who joined the group in 1969. After his retirement (March 2006) the group is led by Leszek Ropelewski.


Many detector designs have been introduced and developed over the years, mostly (but not only) to satisfy the increasingly demanding needs in high-energy physics. They include Multi-Wire Proportional Chambers (MWPC), Drift Chambers (DC), Multi-Step Avalanche Chambers (MSAC), Ring Imaging Cherenkov Chambers (RICH), Multi-Drift Modules (MDM) and Micro-Strip Gas Chambers (MSGC). Dedicated devices have been developed for applications in medicine and biology.

The group's recent activity has been centered on the development of the Gas Electron Multiplier (GEM) technology, invented in 1997 by Fabio Sauli. Sets of medium-size GEM tracking detectors are operating since the early 2000 at the Large Hadron Collider (LHC) at CERN in the experiments COMPASS, TOTEM and the fast LHCb trigger. With the advent of the High-Luminosity LHC (HL-LHC), several systems are under construction replacing the present generation of gaseous devices, limited in rate capability, with GEM-based detectors. The CMS high-eta muon detector will assemble around 40 large size triple-GEM chambers; the ALICE TPC will use arrays of 4-GEM modules as end-cap detector. Similar devices are under development at CERN and other laboratories for fast tracking, improved readout for large volume Drift and Time Projection Chambers and for neutron detection. Applications in other fields are also being developed, including medical imaging, astrophysics and structure analysis.

The GDD group participates to the international research collaboration RD51, Development of Micro-Pattern Gas Detector Technologies, led by L. Ropelewski and S. Dalla Torre. The laboratory is located at CERN in Building 154.

A collection of photos of present, recent and former collaborators to the Gas Detectors Development group can be seen in People.