DIRAC Experiment at CERN: Lifetime Measurement of Pionium
  The DIRAC experiment, a magnetic double arm spectrometer, aims to measure the $\pi^+\pi^-$ atom lifetime with 10% precision, using the high intensity 24 GeV/c proton beam of the CERN Proton Synchrotron. Since the value of this lifetime of order $10^{-15}$~s is dictated by strong interaction at low energy, a precise measurement of this quantity enables to study characteristic pion parameters in detail and to submit predictions of QCD to a severe check. 
Juerg Schacher