CERN Accelerating science

Time of flight

Since particle identification based only on energy loss measurement can not be performed in the crossover region of the Bethe-Bloch curves, NA61/SHINE also uses additional and independent particle identification by Time of Flight (ToF) detectors. The ToF-L and ToF-R detectors were inherited from NA49. In order to extend the identification of NA61/SHINE to satisfy neutrino physics needs, a new forward detector (ToF-F) was constructed. It is placed between the ToF-L/R, just behind the MTPCs.

Two walls, ToF-L(eft) and ToF-R(ight), of 4.4 m2 total surface are placed behind the MTPCs. The track length of particles produced in the target is about 14 meters. Each wall contains 891 individual scintillation detectors with rectangular dimensions, each having a single photomultiplier tube glued to the short side. The scintillators have a thickness of 23mm matched to the photocathode diameter, a height of 34mm and horizontal width of 60, 70 or 80mm, with the shortest scintillators positioned closest to the beamline and the longest on the far end.