Abstract:
Abstract: The physics motivation, detector design, triggers, calibration, alignment, simulation,
and overall performance of the very forward CASTOR calorimeter of the CMS experiment are
reviewed. The CASTOR Cherenkov sampling calorimeter is located very close to the LHC beam
line, at a radial distance of about 1 cm from the beam pipe, and at 14.4 m from the CMS interaction
point, covering the pseudorapidity range of −6.6 < 𝜂 < −5.2. It was designed to withstand high
ambient radiation and strong magnetic fields. The performance of the detector in measurements of
forward energy density, jets, and processes characterized by rapidity gaps, is reviewed using data
collected in proton and nuclear collisions at the LHC.
