Extension of the energy-resolved soft x-ray imaging system using two CCD cameras in LHD

An existing imaging system using a soft X-ray CCD (Charge Coupled Device) camera and beryllium (Be) filters installed to a tangential viewport of the Large Helical Device (LHD) has been utilized not only for the measurement of the flux surface shape, but also for the energy resolved imaging in long pulse discharges. In order to obtain simultaneously soft X-ray energy spectra necessary for the analyses of the imaging results, we have extended the present diagnostic system by adding another soft X-ray CCD camera mainly used for the photon counting mode. This new camera has been installed in a vertical viewport and equipped with two mounting disks rotating independently. This setup enables us to choose any combination of Be filter thickness and slit width according to the amount of photon flux, and it can be combined with the kinetic mode operation if temporal resolution is the first priority. The details and capability of the simultaneous measurements of the soft X-ray images and energy spectra are described. (author)