Design and characterisation of a real time proton and carbon ion radiography system based on scintillating optical fibres

This paper describes the design and characterization of a charged particle imaging system composed of a position sensitive detector and residual range detector. The position detector consists of two identical overlying and orthogonal planes each of which consists of two layers of pre-aligned and juxtaposed scin- tillating fibres. The 500 l m square section fibres are optically coupled to two Silicon Photomultiplier arrays using a channel reduction system patented by the Istituto Nazionale di Fisica Nucleare. The resid- ual range detector consists of sixty parallel layers of the same fibres used in the position detector each of which is optically coupled to a Silicon Photomultiplier array by wavelength shifting fibres. The sensitive area of the two detectors is 9 9cm 2 . Characterising the position sensitive and the residual range detec- tors to reconstruct the radiography, is fundamental to validating the detectors’ designs. The proton radio- graphy of a calibrated target in imaging conditions is presented. The spatial resolution of the position sensitive detector is about 150 l m and the range resolution is about 170 l m. The performance of the pro- totypes were tested at CATANA proton therapy facility (Laboratori Nazionali del Sud, INFN, Catania) with energy up to 58 MeV and rate of about 10 6 particles per second. The comparison between the simulations and measurements confirms the validity of this system.