RADIATION HARD PLASTIC SCINTILLATING OPTICAL FIBER SPINNABLETHERMOPLASTIC POLYORGANOSILOXANES

RADIATION HARD PLASTIC SCINTILLATOR FIBERS ARE NEEDED FOR USE IN DETECTORS OF HIGH ENERGY PARTICLES AT THE SUPERCONDUCTING SUPER COLLIDER (SSC). A CLASS OF POLYMERS, POLYORGANOSILOXANES, CAN WITHSTAND RADIATION DOSES UP TO 18 M RAD WITH LITTLE OPTICAL DAMAGE. OTHER OPTICAL POLYMERSDISCOLOR UNDER THESE CONDITIONS. POLYORGANOSILOXANES ARE AVAILABLE COMMERCIALLY AS CROSS-LINKED ELASTOMERS. THEY CANNOT BE HEAT PROCESSED. THE FIRST RAPID, TRANSPARENT, HEAT PROCESSIBLE, LINEAR POLYORGANOSILOXANES HAVE BEEN SYNTHESIZED. THESE MATERIALS CAN BE PROCESSED AT 150 DEGREES CENTIGRADE AND THEREFORE DOPED WITH RADIATION HARD ORGANIC FLUORS. THEY CAN BE MELT SPUN INTO FIBERS BY CONVENTIONAL TECHNIQUES. THE MATERIALS UNDER INVESTIGATION ARE LINEAR COPOLYMERS, POLYDIMETHYLDIPHENYLSILOXANES. ALTHOUGH 100% POLYDIPHENYLSILOXANES ARE OPAQUE SEMICRYSTALLINE MATERIALS, PHENYL GROUPS IMPART RIGIDITY AT 75 WT% DIPHENYL CONTENT, AND THE POLYMER IS RIGID AT ROOM TEMPERATURE. DIMETHYL UNITS WILL BE INCORPORATED INTO THE POLYMER TO IMPEDE CRYSTALLINITY AND YIELD A TRANSPARENT COPOLYMER. PHASE I WILL INVESTIGATE POLYMERS WITH 80 TO 95%DIPHENYL CONTENT WITH VARYING MONOMER SEQUENCE STRUCTURE TO DEMONSTRATE THE FEASIBILITY OF ACHIEVING OPTICAL TRANSPARENCY IN BULK MATERIALS (ATTENUATION LENGTH GREATER THAN 2 M). RADIATION HARDNESS WILL BE VERIFIED. MEASUREMENTS WILL BE MADE ON TRANSPARENCY AND SCINTILLATION LIGHT OUTPUT. MECHANICAL AND THERMAL ANALYSIS WILL CHARACTERIZE THE THERMOPLASTIC NATURE OF THESE POLYMERS.