To address the demanding requirements for high-sensitivity and high-temporal-resolution diagnostics of weak X-ray spectral signals in frontier experiments such as high-energy density physics (HEDP) and inertial confinement fusion (ICF), a high-sensitivity time-resolved X-ray spectroscopy diagnostic technology based on complex curved (multi-cone) crystal has been developed and implemented. Aiming at the critical bottlenecks including the non-analytical expression of complex curved crystal profiles, the unknown boundaries of fabrication processes, and the difficulties in assembly calibration and positioning, the team independently developed an X-ray diffraction simulation software (XCD) for non-analytical surfaces. This software enables quantitative digital signal prediction and full-process error boundary analysis. In terms of fabrication, breakthroughs were achieved in discretized data reconstruction, magnetorheological finishing, and high-precision bonding, successfully yielding a multi-cone curved crystal element with an effective area of 50 × 60 mm² and an RMS surface profile accuracy of 37.7 nm. Regarding assembly and calibration, a co-twelve-dimensional precision mechanical adjustment system combined with the "copying" calibration method was established. This realized 50-μm-level precision calibration of the X-ray focal line position in the laboratory, successfully solving the coupling challenge between the ultra-narrow focal line and the streak camera cathode. Experimental results demonstrate that the system achieves a line intensity ratio consistency of 96.9% and effectively eliminates irregular spectral modulation, yielding a spectral resolution of 1287 @ 3705 eV and a peak full-spectrum intensity gain of up to 489-fold. Capitalizing on these advantages, this technology was applied to acquire the first worldwide ≤10 ps high-time-resolved data of characteristic spectra from the implosion hot spot under low-doping-ratio conditions. Furthermore, it enabled the first acquisition of time-resolved energy spectra for 0.1% trace-doped elements, revealing the density-driven over-ionization and recombination mechanisms of silicon plasmas, and obtaining the vanadium EXAFS signals with the best signal-to-noise ratio in current international static laser experiments. This technology effectively supports the precision diagnostics of X-ray energy spectra in weak radiation fields under extreme transient conditions such as warm dense matter and shock wave physics.

Complex curved crystal,Time-resolved X-ray spectroscopy,XCD software,High-sensitivity diagnostics,Inertial confinement fusion (ICF)