A Segmented Total Energy Detector (sTED) optimized for $(n,\gamma )$ cross-section measurements at n_TOF EAR2

Abstract

The neutron time-of-flight facility n_TOF at CERN is a spallation source dedicated to measurements of neutron-induced reaction cross-sections of interest in nuclear technologies, astrophysics, and other applications. Since 2014, Experimental ARea 2 (EAR2) is operational and delivers a neutron fluence of $4\times 10^7$ neutrons per nominal proton pulse, which is 50 times higher than the one of Experimental ARea 1 (EAR1) of $8\times 10^5$ neutrons per pulse. The high neutron flux at EAR2 results in high counting rates in the detectors that challenged the previously existing capture detection systems. For this reason, a Segmented Total Energy Detector (sTED) has been developed to overcome the limitations in the detectors response, by reducing the active volume per module and by using a photomultiplier (PMT) optimized for high counting rates. This paper presents the main characteristics of the sTED, including energy and time resolution, response to $\gamma$-rays, and provides as well details of the use of the Pulse Height Weighting Technique (PHWT) with this detector. The sTED has been validated to perform neutron-capture cross-section measurements in EAR2 in the neutron energy range from thermal up to at least 400 keV. The detector has already been successfully used in several measurements at n_TOF EAR2.

References in corpus (4)

• The 7Be(n,alpha)4He reaction and the Cosmological Lithium Problem: measurement of the cross section in a wide energy range at n_TOF (CERN)
• Design of the third-generation lead-based neutron spallation target for the neutron time-of-flight facility at CERN
• Measurement and analysis of the Am-243 neutron capture cross section at the n_TOF facility at CERN
• First measurement of the ${}^{94}$Nb($n$,$\gamma$) cross section at the CERN n\_TOF facility