A five-channel proton detector (PD) based on Passivated Implanted Planar Silicon (PIPS) detectors has been developed and installed on the HL-3 tokamak to measure protons and tritons ( \(^3\text {H}^+\) ions) produced by the D–D fusion branch d(d,p)t. Featuring tungsten shielding, platinum foils, and optimized collimators for noise suppression, the system design was informed by a self-developed Monte Carlo code (CFPMC) employing a fourth-order Runge–Kutta method to simulate proton trajectories and optimize detector placement. During the 2024 experimental campaign, initial results confirmed the system’s ability to measure proton flux with temporal and pitch angle resolution during neutral beam injection (NBI) discharges. Clear modulation of proton signals by sawtooth crashes was observed, with distinct responses across different channels, consistent with the sampling of different plasma regions relative to the \(q = 1\) surface. The forward source-tracing simulations reproduce the channel-dependent spatial birth distributions in the poloidal plane and yield pitch angle distributions in good agreement with the measured data. These results demonstrate both the feasibility of the PD diagnostic and the fidelity of the modeling, highlighting the system’s preliminary spatially resolving capability for D–D fusion protons in HL-3 plasmas. The combined diagnostic modeling approach offers a promising framework for studying fast-ion redistribution and MHD-induced modulations of fusion reactivity in future HL-3 discharges.
