A compact, light scintillating fiber tracker with SiPM readout

We present the concept of a novel compact and light tracker based on arrays of plastic scintillating fibers readout with Silicon Photomultipliers (SiPMs). The tracker will be composed of multiple planes, with the fibers in each plane oriented perpendicularly to those in the adjacent planes. Each plane will consist of two staggered layers of fibers, having a round cross section with 500 mu m diameter and arranged in a close packed configuration. Scintillation photons produced in the fibers will be collected by SiPM arrays with 250 mu m strip pitch located at one end of the fibers. This configuration will ensure an accurate spatial resolution and a fast response, while keeping a reduced material budget. Hence, this detector will be suitable to track low energy particles and will be able to efficiently detect the Compton scattered electrons produced by gamma rays with energies down to 100 keV. We built a reduced scale tracker prototype, using Hamamatsu 128 channel SiPM arrays and 32 channel PETIROC2A front end ASICs readout. The latter are controlled by a custom data acquisition board with self triggering capabilities. We tested this prototype with cosmic rays, radioactive sources and accelerated particle beams.