The 9th International Conference on Matter and Radiation at Extremes (ICMRE2026) ( ICMRE2026)

In Z-pinch inertial confinement fusion (ICF) research, the primary neutron yield is a critical diagnostic parameter for quantifying implosion performance, fuel-pusher mixing, and thermonuclear ignition. For next-generation 50MA-class Z-pinch facilities, neutron yield diagnostics face challenges of extremely high flux and complex radiation backgrounds. This paper presents the design and simulation of the PROTEX (Proton Recoil Telescope for Yield Extension) system, designed to achieve real-time absolute neutron yield measurement with a wide dynamic range of 10¹³ to 10¹⁸ n/shot. The PROTEX system utilizes the n-p elastic scattering principle with a polyethylene CH converter. To optimize the signal-to-background ratio in the intense radiation environment, a single-arm off-axis configuration is adopted. This design effectively shields direct-path neutrons and gammas while minimizing the system's volume and weight.
Using Geant4 Monte Carlo simulations, we systematically optimized key components: (1) a neutron collimator and shielding stack providing >10² contrast between modulated and background neutrons; (2) a tunable neutron-proton converter with adjustable aperture and proton flight path to achieve several orders of sensitivity scaling; (3) analysis of secondary particles produced by conversion film materials and their influence on signal. Through accurate modeling and Monte Carlo simulation calculation, the detection sensitivity and measurement uncertainty of the system are evaluated, combined with shielding design to minimize the background signal, which lays a theoretical foundation for subsequent engineering implementation.
Simulations indicate that under maximum DT yield (10¹⁸ n/shot), the SiPIN output current remains below saturation. The combination of aperture adjustment, flight distance variation, and gain switching enables about 6 orders of dynamic range adjustment. The PROTEX system offers a robust, realtime, and direct neutron yield measurement solution for high-flux Z-pinch fusion experiments.

Z-pinch,Neutron yield diagnostic,Proton recoil,Geant4 simulation,Real-time measurement