Tetra-Ball: design of a new type of extended energy range single-sphere neutron spectrometer

Abstract

Tetra-Ball (T-Ball) is a new type of extended energy range single-sphere neutron spectrometer. Compared to its predecessor, the SP², it reduces the number of sensors from 31 to 21. This is achieved with a tetrahedric disposition of the sensors. The polyethylene spherical moderator is 28 cm in diameter and includes a lead insert for the detection of neutrons above 10 MeV. This work describes the T-Ball design and calculates the response matrix considering four different irradiation geometries. The impact of anisotropy effects on the T-Ball spectrometric performance is investigated by simulation. Although this work does not cover the totality of the possible energy distributions and conditions of use, the results suggest that T-Ball could offer adequate spectrometric performance and a good isotropy in most operating scenarios in the high-energy field.