Design for x-ray imaging spectroscopy in Large Helical Device

An assembly of pin-hole camera has been designed for x-ray imaging spectroscopy in Large Helical Device (LHD). In the design the camera basically consists of a 2-D-pixel-array detector, a metallic filter, and a pin hole. The detector measures gray scale images through the filter, while the thickness of the filter changes shot by shot. The gray scale images are mathematically transformed to a color spectral image by means of Mellin transform. The available spectral range is depending on the material of the filter. The spectral energy resolution is also depending on the material of the filter and the intensity of incident x-ray. In the case of the filter made of aluminum, the spectral range is theoretically predicted to be from 3.0 keV to 30 keV. It is also theoretically expected in the case of typical LHD plasmas that 50 flames of color spectral 32×32-pixel-image is obtained per second with a spectral resolution of E/ΔE = 4.3 at a photon energy of E = 5.0 keV. (author)