Experimental study and analysis on the spatial resolution of pulse-dilation X-ray imagery

This is the authors' abstract. We don't add key points for this paper.

In laser fusion ignition, high-temperature and high-pressure hot spots form and sustain self-sustained burn in tiny regions with diameters of tens of micrometers. As the only feasible two-dimensional imaging diagnostic technique for laser fusion research, framing camera technology plays a vital role in characterizing the temporal evolution of the fusion burn process. The spatial resolution of such diagnostics directly determines the observability of plasma dynamic evolution during the ignition phase. To upgrade diagnostic performance and achieve higher spatial resolution, we developed a pulse-dilation X-ray Imager (PDXI) system equipped with a precision amplitude-modulated resolution cathode for quantitative calibration, and constructed an adjustable magnetic focusing system with a maximum field strength of 8000 Gauss (Gs). On this integrated platform, we systematically analyzed the impacts of focusing magnetic field strengths (MFS), the distance between MCP and fluorescent screen (D MCP-FC ), and the space between PC and anode mesh (S PC-AM ) configuration influence PDXI spatial resolution performance. Experimental results demonstrate that the spatial resolution of PDXI varies non-monotonically with MFS, increasing first and then decreasing with rising field strengths. The optimal spatial resolution reaches 25 lp/mm (contrast transfer function (CTF) = 13%), representing a remarkable advance in X-ray imaging for inertial confinement fusion (ICF) diagnostics. The spatial resolution of PDXI is effectively boosted to 25 lp/mm through systematic experimental optimization. This work identifies the key parameters governing system resolution and provides a clear technical path for further optimization, laying a solid foundation for the development of next-generation laser fusion diagnostic instruments.