Design solutions for the hodoscope of the magnetic proton recoil neutron spectrometer of the SPARC tokamak

M Dalla Rosa; S Mackie; D Rigamonti; L G Tedoldi; S Colombi; A Dal Molin; G Marcer; M Nocente; G Gorini; P Raj; M Rebai; J Carmichael; M Reinke; F Scioscioli; R A Tinguely; M Tardocchi

doi:10.1063/5.0219463

Design solutions for the hodoscope of the magnetic proton recoil neutron spectrometer of the SPARC tokamak

Rev Sci Instrum. 2024 Aug 1;95(8):083508. doi: 10.1063/5.0219463.

Authors

M Dalla Rosa¹, S Mackie², D Rigamonti³, L G Tedoldi¹, S Colombi¹, A Dal Molin³, G Marcer¹, M Nocente¹, G Gorini¹, P Raj⁴, M Rebai³, J Carmichael⁴, M Reinke⁴, F Scioscioli³, R A Tinguely², M Tardocchi³

Affiliations

¹ Department of Physics, University of Milano-Bicocca, Milan 20126, Italy.
² Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
³ Institute for Plasma Science and Technology, National Research Council, Milan 20125, Italy.
⁴ Commonwealth Fusion Systems, Devens, Massachusetts 01434, USA.

PMID: 39093115
DOI: 10.1063/5.0219463

Abstract

A new 14 MeV neutron spectrometer utilizing the magnetic proton recoil (MPR) technique is under development for the SPARC tokamak. This instrument measures neutrons by converting them into protons, whose momenta are subsequently analyzed using a series of magnets before detection by an array of scintillators known as the hodoscope. In this work, we explore various solutions for the hodoscope detectors through laboratory tests with radioactive sources and simulations. We present findings on light collection and pulse shape discrimination based on detector types, as well as optimal solutions for photo-detectors studying the differences between SiPM and PMT. Our results also led to the determination of a better optimized design for the hodoscope detectors, consisting of a 0.7 cm width and a 13 cm length EJ276D scintillation rod.