Recoil Proton Telescopes and Parallel Plate Avalanche Counters for the $^{235}$U(n,f) cross section measurement relative to H(n,n)H between 10 and 450 MeV neutron energy

With the aim of measuring the $^{235}$U(n,f) cross section at the n_TOF facility at CERNover a wide neutron energy range, a detection system consisting of two fission detectors and threedetectors for neutron flux determination was realized. The neutron flux detectors are RecoilProton Telescopes (RPTs), based on scintillators and solid state detectors, conceived to detectrecoil protons from the neutron-proton elastic scattering reaction. This system, along with afission chamber and an array of parallel plate avalanche counters for fission event detection, wasinstalled for the measurement at the n_TOF facility in 2018, at CERN.An overview of the performances of two RPTs — especially developed for this measurement — and of theparallel plate avalanche counters are described in this article. In particular, the characterizationin terms of detection efficiency by Monte Carlo simulations and response to neutron beam, the studyof the background, dead time correction and characterization of the samples, are reported. Theresults of the present investigation show that the performances of these detectors are suitable foraccurate measurements of fission reaction cross sections in the range from 10 to 450 MeV.