CMD-3

The CMD-3 experiment at the VEPP-2000 electron-positron collider in Novosibirsk studies e+e annihilation to hadrons in the wide center-of-mass energy range.

One of important and insufficiently known processes is the neutron-antineutron pairs production near the reaction threshold. The typical delay between bunch-crossing time and antineutron annihilation time is of order of few nanosecond (4–10). Consequently time-of-flight system with time resolution of about 1 nsec becomes the important part of the CMD-3 detector upgrade. A very thin TOF counter composed of scintillating strips with WLS fiber readout from both sides by SiPMs will be developed. The TOF system will consist of 220 scintillating strips of varying thickness (5–7 mm), total number of electronic channels is 440. Such counters should fit into the very narrow space available in the detector.

The calorimetry in the detector is based on three subsystems: closest to the beam pipe barrel liquid xenon calorimeter, outer barrel calorimeter based on CsI scintillation crystals, and endcap calorimeter made of BGO scintillation crystals.