Response of TAPS to monochromatic photons with energies between 45 and 790 MeV

Abstract

The Two Arm Photon Spectrometer TAPS — comprising 384 plastic-BaF 2 scintillator telescopes - was tested with monochromatic photons in the energy range between 45 and 790 MeV. The energy resolution for a collimated photon beam hitting the central detector module was determined to σ/E = 0.59% × E γ − 1 2 + 1.9% (E γ given in GeV) . For the the fast scintillation component alone σ/E = 0.79% × E γ − 1 2 + 1.8% has been measured. The position resolution of the point of impact amounts to Δx = 2 cm (FWHM) at the highest energies which corresponds to 30% of the diameter of an individual module. Monte Carlo simulations using the code GEANT3 are in good agreement with the experimental results.