The development of a back-illuminated supportless CCD for SXI onboard the NeXT satellite

We give an overview, the current status and future plan of the development of the Soft X-ray Imager (SXI) onboard the NeXT (Non-thermal Energy eXploration Telescope) satellite proposed to be launched around 2010. The SXI is a back-illuminated supportless CCD (a combination of “back-illuminated CCD” and “supportless CCD”) whose imaging area size and the supportless region are 42mm×42mm and 30mmφ, respectively. The goal of the depletion layer of the CCD is 300μm, which enable us to cover the X-ray energy range of 0.5-20 keV. The first test model of the supportless CCD shows no performance change due to the thinning process of the CCD. We have already started processing the evaluation model 'CCD-NeXT1', which will be completed at the end of 2004. We are also studying the camera system, the focal plane assembly including thermal electric cooler (TEC) and electronics as well as the CCD chip.