Experiment description

• Antiprotons (red) circulate in the LEAR ring
  • many millions per second
  • deflected by dipoles (blue)
    (there are four of those, one in each corner of the accelerator, here, only one is plotted)

• Xenon clusters (atoms freezed together) cross the path of the antiprotons

• When an antihydrogen atom (red with blue positron circulating around it) is produced (see Antihydrogen production)
  • it is not deflected in the dipole, goes straight through
  • it leaves the LEAR ring

• In the first detector (red box)
  • the antihydrogen is 'ionized', i.e. positron and antiproton are separated
  • the positron
    • sticks in this detector
    • its former kinetic energy is measured
    • annihilates with an electron
    • 2 photons of 511keV each are emitted back-to-back
      and measured
  • the antiproton
    • passes several detectors, measuring
      • velocity
      • sign of charge
• The combination of
  • a positron
  • an antiproton
  with right velocities and energies is a clear and sufficient indication that an antihydrogen atom has been produced and detected.

Specialists read the preprint