The PERDaix scintillating fiber tracker

We present the results of the Proton Electron Radiation Detector Aix-la-Chapelle (PERDaix) which is a detector for charged cosmic rays of energies between 0.5 GeV and 5 GeV built around a novel scintillating fiber tracker with a spatial resolution of 50 μ m and a permanent magnet. The experiment was launched as part of the payload of a statosphere balloon in the framework the Ballon EXperiments for University Students programme. We show the performance of the tracker during the operation on ground and during a four hour flight during which a float altitude of 33 km was achieved, recording over 150,000 charged particles. The scintillating fibers were read out by silicon photomultiplier arrays. The complete system was designed to operate from ambient temperatures betweeen -60 C and soft vacuum conditions to 20 C and standard atmospheric pressure without active temperature regulation. We discuss the track-based alignment, the momentum resolution and the effect of temperature variation and silicon photomultiplier noise on the track reconstruction efficiency.