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

Abstract

The Two Arm Photon Spectrometer TAPS — comprising 384 plastic-BaF₂ 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 $\text{σ/E = 0.59\% × E}{}_{\mathrm{\gamma }}{}^{\mathrm{<mtext>-</mtext><mtext>1</mtext><mtext>2</mtext>}}\text{+ 1.9\% (E}{}_{\mathrm{\gamma }}\text{given in GeV}\text{)}$. For the the fast scintillation component alone $\text{σ/E = 0.79\% × E}{}_{\mathrm{\gamma }}{}^{\mathrm{<mtext>-</mtext><mtext>1</mtext><mtext>2</mtext>}}\text{+ 1.8\%}$ 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.