High resolution scintillating-fibre hodoscope and its readout using peak-sensing algorithm

A pair of new hodoscopes made of 0.28 mm Ø scintillating fibre have been built and tested at T11 beam line of CERN PS. They consist of seven layers of fibres, and are read out using multi-anode photomultipliers. The average number of photoelectrons produced by a minimum ionizing particle is found to be about 11, which resulted in a very high detection efficiency (98.6%) at an appropriate threshold setting. The hit multiplicity for single-hit events was suppressed to 1.12 at this threshold setting, thanks to the Peak-Sensing Circuit used for the readout. A spatial resolution of ∼ 75 μ m and a time resolution of ∼ 0.56 ns (both in RMS) have been obtained with these hodoscopes. Further detailed study of the detector response such as double hit efficiency at very close distances, dependence on the incident angles has been performed.