The H1 very forward proton spectrometer at HERA

The very forward proton spectrometer, VFPS, is a component of the H1 detector at the HERA collider. Scattered protons emitted with a polar angle less than 1 mrad and carrying a fractional energy 1 − x P , 0.008 < x P ≤ 0.028 of the incident proton beam energy can be detected by scintillating fiber detectors which are read out by position sensitive photo-multipliers. These detectors are contained in Roman pot stations which are moved close to the circulating proton beam. The structure, operation and performance of the two Roman pot stations located at about 220 m from the H1 interaction point in the cryogenic section of the proton ring are described.