Design and Simulation of the ∆E-E Silicon Telescope for the ⁶Li(n,t)⁴He Reaction at CSNS

[Methods]: Using the Geant4 Monte Carlo code, the energy range of tritons produced by the 6Li(n,t)4He reaction for incident neutrons in the 4‑7 MeV range was simulated. The energy deposition behavior of tritons within this energy range in silicon was further simulated to determine the appropriate thicknesses of the ΔE and E detectors. After validating the reasonableness of a single ΔE‑E silicon telescope unit, a telescope array consisting of 10 detector units was designed, covering five backward angles (95°–155°) and five forward angles (25°–85°).

Under the CSNS neutron energy spectrum, the counting distributions of tritons and other secondary particles from the 6Li(n,t)4He reaction on the ΔE‑E silicon telescope were simulated. The 6LiF target adopted a three‑layer structure (target–Al foil–target) with an Al foil thickness of 285 μm and a single LiF layer thickness of 5 μm, oriented at 65° relative to the neutron incident direction. [Results]: The simulation results determined the optimal detector thicknesses to be 40 μm for the ΔE detector and 300 μm for the E detector, ensuring that tritons penetrate the thin detector and stop in the thick one.

The designed ΔE-E silicon telescope array enables efficient discrimination between tritons and other secondary particles generated by the 6Li(n,t)4He reaction within the 4-7 MeV neutron energy region under the CSNS spectrum. [Conclusions]: This work provides a theoretical basis for subsequent experimental designs aimed at measuring the 6Li(n,t)4He reaction cross-section at the CSNS platform.