X-ray framing camera (XFC) is usually used as the principal diagnostic tool in inertial confinement fusion research. The methods on how to precisely calibrate the temporal resolution are important topics for XFC with several picoseconds gate time. A method to measure the temporal resolution of XFCs is proposed based on a high-power subpicosecond ultraviolet laser facility called LLG-ultimate. In our method, series of duraluminium alloy stepped reflective surfaces are used to separate the incident laser beam into sequentially delayed beams with equal size, spacing, and time interval. The temporal resolution of XFC can be measured if the sequentially delayed beams irradiate a gold photocathode microstrip line while the high-voltage pulse transferring along the same area simultaneously. A Fabry–Perot etalon is placed in the light path, improving the probability of synchronization of the voltage pulse and laser pulse. The accuracy of this measurement method can be very high by reducing the time interval of the sequentially delayed beams.
Areal density (ρR) is one of the crucial parameters in the inertial confinement fusion. Measurement of the fusion products is a more feasible method to diagnose ρR than other methods, such as X-ray. In the capsules filled with D2 fuel or D-3He fuel, proton is an ideal probe to diagnose the implosion ρR in different emission times and directions by measurements of the proton yields and spectra. By D-D reaction protons and D-3He reaction protons, the diagnostics of the total and fuel ρR, ρR evolution, implosion asymmetry and mix effect have been demonstrated at OMEGA and NIF facilities. Also some advanced proton diagnostics instruments are developed with a high level capability. Preliminary diagnosis of ρR in the deuterium involved fuel capsules by measurement of protons at SG-III facility was implemented. A fusion product emission and transport code by Monte-Carlo method was developed. The primary and secondary protons emission and transport in the fuel and shell plasmas were able to be simulated. The relations of the proton energy loss and the secondary proton yields with the areal density were inspected. Several proton spectrometers have been built up at SG-III facility, such as a step ranged filter (SRF) proton spectrometer and a wedged range filter (WRF) proton spectrometer. Some proton response simulation codes and the codes for proton spectra reconstruction were also developed. The demonstrations of ρR diagnostics at SG-III facility by D-D reaction and D-3He reaction proton spectra measurements are presented.
The combination of electron beam lithography (EBL) and x-ray lithography (XRL) has been developed to successfully fabricate x-ray transmittive diffractive optical elements (DOE) such as Fresnel zone plates (FZP) and transmittive gratings (TG). In fabrication processes, the master masks of FZP and TG were patterned with high resolution on free standing membranes by EBL and followed by electroplating. Subsequently, the final gold FZP and TG with vertical cross section were efficiently and economically replicated by XRL and electroplating. By using this combined method, FZP based on silicon nitride (SiNx) free standing membrane was achieved with 150 nm width of outermost ring and 6.7 high aspect ratio, due to a novel sandwich resist structure. A series of TG master masks (2000 g/mm, 3333 g/mm, and 5000 g/mm) were fabricated by EBL. Furthermore, final gold TGs with 2000 g/mm and 3333 g/mm were replicated by XRL. The spectrum of 2000 g/mm TG has shown its perfect performance in x-ray spectroscopy.