A cryogenic magnetic detector for storage ring experiments

A cryogenic magnetic detector (CMD) for colliding beams experiments with VEPP-2M storage ring has been made. A distinctive feature of this detector is its operation at low temperature to get a higher density of the gas mixture in the optical spark chamber, which allows a spatial resolution of about 50 μm. A momentum resolution σp/p=0.05p(GeV/c) has been reached at the 32 kG magnetic field generated by the superconducting solenoid. Only charged particles are detected.