L3 experiment

[3] It started up in 1989 and stopped taking data in November 2000 to make room for construction of the Large Hadron Collider (LHC).

Now, the ALICE detector sits in the cavern that L3 used to occupy, reusing L3's characteristic red octagonal magnet.

[4] The L3-detector was a multi-layered cylindrical set of different devices, each of them measuring physical quantities relevant to the reconstruction of the collision under study.

Starting from the centre, close to the pipe where electrons and positrons circulate and collide, there were first the Silicon strip Microvertex Detector (SMD)[5] and the Time Expansion Chamber (TEC).

One also gathered information about the momentum (a quantity related to mass and energy) of the particles by measuring their deflection in the magnetic field present in the detector.