Development of X-ray imaging spectroscopy sensor with SOI CMOS technology

• Main Authors: Ryu, S G, Tsuru, T G, Nakashima, S, Arai, Y, Takeda, A, Miyoshi, T, Ichimiya, R, Ikemoto, Y, Takashima, R, Imamura, T, Ohmoto, T, Iwata, A
• Format: Conference Proceeding
• Language: English
• Subjects: Active pixel sensor (APS); CMOS integrated circuits; correlated double sampling (CDS); Energy resolution; intra-pixel trigger; Noise; Pixel; readout noise; Silicon; Silicon on insulator technology; Silicon-On-Insulator (SOI); X-ray; X-ray imaging
• ISSN: 1082-3654; 2577-0829
• DOI: 10.1109/NSSMIC.2010.5873714

We have been developing a monolithic active pixel sensor with the 0.2 μm Silicon-On-Insulator (SOI) CMOS technology, i.e. SOIPIX, for the X-ray imaging spectroscopy on future astronomical satellites. SOIPIX includes a thin CMOS readout layer and a thick high-resistivity Si-sensor layer vertically on a single chip, which would provide advantages in capabilities of direct and flexible readout circuitries over charge-coupled device (CCD). We have built INTPIX2/3 (2008/2009) and XRPIX1(2010). We successfully confirmed the capability of X-ray imaging and spectroscopy in a photon-counting mode by irradiating INTPIX2/3 with monochromatic X-rays. To reduce the readout noise, we designed and built XRPIX1, which has a correlated double sampling (CDS) readout circuit in each pixel to suppress the reset noise. We obtained an energy resolution of FWHM ~1.5 keV(7%)@22 keV with XRPIX1 cooled at 50 degree. Moreover, XRPIX1 offers intra-pixel hit trigger and one-dimensional hit-pattern outputs. We also confirmed the trigger capability by irradiating a single pixel of XRPIX1 with laser light.