Electromagnetic calorimetry using scintillating plastic fibres

Abstract

When used in lead-scintillator sandwich calorimetry, scintillating optical fibres offer a new way to achieve fine grain sampling and thereby to improve the energy and spatial resolution of a technique still unbeaten for timing and compactness. A small calorimeter element made of planes of 0.9 mm diameter fibres alternating with Pb plates has been built and tested in an electron beam. An energy resolution of $\text{σ}{}_{\mathrm{E}}\text{/√E⋍9.8}\text{and}\text{7.8\%}$ was obtained with 1 and 0.5 mm Pb plates, respectively. The parameters of the fibres have been measured. Calculations performed with a refined version of the EGS code reproduce these results and suggest improved Pb-fibre calorimeters rivalling with Pb glass in energy resolution.