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Experimental research on radiation induced changes of polymer optical fiber under gamma-ray irradiation

Under the high energy irradiation, the charges (even little) of molecules of polymer can cause the physical and chemical characteristics evident changes of polymer. The physics and chemical mechanisms which are responsible for radiation induced loss was analyzed. The radiation damage of polymethylmethacrylate (PMMA), Polystyrene PS and polycarbonate (PC) optical fiber under γ-ray irradiation was researched experimentally. The visible light transmission of the POF under different irradiation dose was measured. The results indicated that the radiation damage of three kinds of POF was wavelength-dependent. Under lower dose below 1KGy, the transmission rate decreased identical in the whole visible light range. When the irradiation dose exceeded 5KGy, the transmission rate reduced obviously, and the recovery indicated that the visible light transmission rate of the POF in the range of 400nm to 500nm comparing with 600nm to 800nm, decreased seriously under the irradiation dose exceeded 5kGy. The transmission rate of both PMMA and PC have an evident peak value at the range 550nm-650m, and that of PS has a wide band at the range 500-700nm. We also measured the recovery of three kinds of POF under different irradiation dose by measuring several times the POF after stopping irradiating.