Highest energy physics experiments in CERN

TOTEM

• Telescopes of "Roman pots" placed symmetrically on both sides of the intersection region. They will detect protons scattered at very small angles in elastic or quasi-elastic reactions.
• A forward inelastic detector covering about 4 pseudorapidity units in the forward cones (from eta=3 up to eta=7) with full azimuthal acceptance. This detector will measure the overall rate of inelastic reactions.

The Roman pots are special devices mounted on the vacuum chamber of the accelerator. In its retracted position the Roman pot leaves the full aperture of the vacuum chamber free for the beam as required at the injection.

Once the final energy is attained and the circulating beams are stable, the Roman pot is moved toward the machine axis by compressing the bellows until the inner edge of the detectors reaches a distance of the order of one millimeter from the beam. Particles emitted at very small angles can therefore be detected.