The energy selected hot-spot X-ray emission image measurement in indirectly-driven implosions on SG-III facility by a multi-channel spatial flat-response KB microscope

The 2D hot spot X-ray emission image diagnostics, including the shape and the fine structure, are very important in the ICF implosions. Some advanced X-ray imaging systems with high spatial resolution and energy selection are required. The system with a multi-channel KB microscope and a gated X-ray detector has been developed on NIF and OMEGA. On SG-III facility, a 8-channel KB microscope was developed with the periodic multilayer mirrors. Due to the small grazing angle bandwidth, the reflectivity varied rapidly with the incident angle. The reflectivity flatness in the field-of-view (FOV) was poor. The measured image would be modulated with the spatial reflectivity response. Recently, a new 4-channel KB microscope with a spatial flat response was developed on SG-III facility. The Pt single-layer mirrors were adopted. A passing energy band of 5.7-7.1keV was obtained by the K-edge of a Fe filter. The FOV range was larger than 1mm. The variation of the reflectivity was less than 10% in a FOV range of 400μm and less than 20% in a range of 800μm. The estimated spatial resolution was about 5μm. The designed magnification was 21, and the covered solid angle was higher than 10^-7 sr. The polar asymmetry of the hot spot X-ray emission was diagnosed in an equatorial view on SG-III facility.