NA61/SHINE detector

The NA61/SHINE detector is a large-acceptance hadron spectrometer situated in CERN North Area. Beam delivery to the detector occurs via the H2 beamline from the Super Proton Synchrotron (SPS). Three Beam Position Detectors (BPDs) and a set of scintillator counters (S1, S2, V1) are utilized upstream of the spectrometer to measure beam position and time references.

The detection system consists of four Time Projection Chambers (TPCs) responsible for tracking charged particles produced in collisions. Positioned downstream of the target and along the beamline are two Vertex TPCs (VTPCs) enclosed within superconducting magnets with a combined bending power of up to 9 Tm. The magnetic field is scaled proportionally to the beam momentum to maintain momentum acceptance similar for different collision energies. Placed symmetrically on both sides of the beamline, downstream of the VTPCs, are the Main TPCs (MTPCs) and two walls of pixel Time-of-Flight (ToF-L/R) detectors. The VTPCs are filled with an Ar:CO gas mixture in the ratio 90:10, while the MTPCs utilize a mixture of 95:5.

Downstream of the MTPCs, the Projectile Spectator Detector (PSD) is located. It is a high-resolution calorimeter centered on the beam. It measures the energy flow around the beam direction allowing for selecting the desired collision centrality.