Measurements of optical properties of waveshifting optical fiber for liquid scintillator hadron calorimetry

Abstract

Measurements have been made on optical properties of Bicron BCF91 waveshifting optical fiber. This fiber is proposed as a means of converting blue and UV light emitted from liquid scintillator when exposed to ionizing radiation. The conversion is accomplished by coiling the fiber in a reservoir filled with liquid scintillator and coated internally with reflective paint. Blue and UV light is absorbed by the waveshifting dyes in the fiber and reemitted in the green portion of the spectrum. Some of the reemitted light is channeled into the core of the fiber and out to photodetectors. It has been proposed to outfit the hadron calorimeter subsystem of the proposed GEM detector, to be built at the Superconducting Super Collider, with 800 000 separate liquid scintillator/waveshifting fiber cells. The measurements described in this work deal with the spectral properties of the fiber: spectral responsivity, spectral emissivity, and attenuation as a function of wavelength and propagation length. The theoretical response of an ideal calorimeter cell is studied based on the results of the measurements presented in this paper.