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

TL;DR

This paper describes the development and characterization of recoil proton telescopes and parallel plate avalanche counters used in measuring the $^{235}$U(n,f) fission cross section across 10 to 450 MeV neutron energies at CERN's n_TOF facility.

Contribution

It introduces a detection system with specialized detectors and provides detailed performance characterization for accurate high-energy neutron-induced fission measurements.

Findings

Detectors show high efficiency and suitable response for 10-450 MeV neutron energies.

Monte Carlo simulations effectively characterize detector performance and background.

The system enables precise cross section measurements at high neutron energies.

Abstract

With the aim of measuring the $^{235}$U(n,f) cross section at the n\_TOF facility at CERN over a wide neutron energy range, a detection system consisting of two fission detectors and three detectors for neutron flux determination was realized. The neutron flux detectors are Recoil Proton Telescopes (RPT), based on scintillators and solid state detectors, conceived to detect recoil protons from the neutron-proton elastic scattering reaction. This system, along with a fission chamber and an array of parallel plate avalanche counters for fission event detection, was installed 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 the parallel plate avalanche counters are described in this article. In particular, the characterization in terms of detection efficiency by Monte Carlo simulations and response to neutron beam, the study of the background, dead time correction and characterization of the samples, are reported. The results of the present investigation show that the performances of these detectors are suitable for accurate measurements of fission reaction cross sections in the range from 10 to 450~MeV.