Influence of polystyrene scintillator strip methods of production on their main characteristics

The baseline option for Target Tracker of OPERA detector is plastic scintillator strips, 6.7 m length, read with wavelength shifting (WLS) fiber. Usually such strips are supposed to be obtained by extrusion from pellets. Despite many advantages of extrusion process the strips extruded from pellet strips have low attenuation length (BAL=20-40cm) and low yield (LY). The main idea of our new method was to obtain scintillator using extrusion method but from the melt of specially polymerized plastic. Pilot setup was created and pilot batch for OPERA prototype was obtained with the 10 kg/h productivity. Still, for mass production there was a necessity to adapt the production scheme and to manage quality assurance and quality control system. During mass production of scintillator strips for OPERA detector we have implemented all obtained results into production process. And we have carefully studied their influence on strip quality. The achieved average light yield is 7.2 ph.el. for OPERA strips.