COmmon Muon and Proton Apparatus for Structure and Spectroscopy


COMPASS is a high-energy physics experiment at the Super Proton Synchrotron (SPS) at CERN in Geneva, Switzerland. The purpose of this experiment is the study of hadron structure and hadron spectroscopy with high intensity muon and hadron beams.

On February 1997 the experiment was approved conditionally by CERN and the final Memorandum of Understanding was signed in September 1998. The spectrometer was installed in 1999 - 2000 and was commissioned during a technical run in 2001. Data taking started in summer 2002 and continued until fall 2004. After one year shutdown in 2005, COMPASS resumed data taking with a muon beam in 2006 and 2007. The years 2008 and 2009 were dedicated to the COMPASS hadron spectroscopy programme with pion and proton beam. In 2010 structure function measurements with a polarised proton target will continue.

Nearly 240 physicists from 11 countries and 28 institutions work in COMPASS.