A Multipurpose Scintillating Fibre Beam Monitor for the Measurement of Secondary Beams at CERN

A scintillating fibre beam monitor has been developed at CERN for the measurement of low energy and low intensity secondary beams. This monitor can track the passage of individual particles up to intensities of 10⁷ particles per second per mm², over an active area of 20 cm x 20 cm, and with a spatial resolution of 1 mm. Thanks to an external trigger system, the achieved detection efficiency is 95% and the noise level is kept below 10⁻⁴ events/second. The simple design of this monitor avoids the common production difficulties of scintillating fibre detectors and makes its maintenance easier, when compared to other tracking detectors, due to the absence of gas or cooling. Using special electronics, a version of the monitor can also be used for time-of-flight measurements, achieving a time resolution of 900 ps. Thanks to its versatility, the monitor will perform several functions when measuring the secondary beams of the CERN Neutrino Platform: beam profile, position and intensity measurement, magnetic momentum spectrometry, particle identification through time-of-flight, and trigger generation for the experiments.