Light transport in long, plastic scintillators

As a form of the input into the collaboration the group from the Andrzej Sołtan Institute for Nuclear Studies undertook a task of investigating the validity of the design of a compact detector for Gamma Ray Bursts photon polarization measurements, known as POLAR. The authors focused at the scintillation and light transport properties of (200×6×6)mm3 BC400 plastic bars as well as of other samples of BC408 plastic in the attempt to determine whether the assembled instrument is going to achieve the performance criteria bestowed upon it by the project. The investigation revealed a strong dependence between the amplitude of a signal and distance between the precursor interaction in a scintillator and the photodetector. Accordingly to this finding an attempt has been made to determine the influence of the surface polishing quality on the overall scintillator performance. The authors consider that proper machining of scintillator pieces, adequate choice of their packaging, and proper software analysis may overcome the revealed disadvantages.