A 256 energy bin spectrum X-ray photon-counting image sensor providing 8Mcounts/s/pixel and on-chip charge sharing, charge induction and pile-up corrections

Abstract : To achieve better and faster material discrimination in applications like security inspection, X-Ray image sensors giving a highly resolved energy spectrum per pixel are required. In this paper, a new pixel architecture for spectral imaging is presented, exhibiting a 256 bin spectrum per pixel in a single image duration, up to two orders of magnitude higher than previous works. A prototype circuit, composed of 4x8 pixels of 756$\mu$mx800$\mu$m and hybridized to a CdTe crystal, was fabricated in a 0.13$\mu$m process. Our pixel architecture has been measured at 8 Mcounts/s/pixel while embedding on-chip charge sharing, charge induction and pile-up corrections