SpacePix3: SOI MAPS detector for space radiation monitoring

Abstract The SpacePix3 monolithic active pixel sensor is a novel ASIC for space radiation monitoring designed in a 180 nm SOI CMOS technology. The detector is capable of detecting and differentiating protons, electrons, and heavy ions. Its active sensor area is 3.84×3.84 mm 2 , pixel matrix is arranged in a 64×64 square array with 60 µm pitch. The pixel front-end amplifier signal range is 1–80 ke - , extended up to 30 Me - using a backside channel. Diodes integrated in the handle wafer in each pixel are biased at -150 V, creating a depleted layer approximately 35 µm deep. Impinging particle generates a charge pulse converted to a voltage pulse by the charge-sensitive amplifier. Maximum voltage memorized by the peak detector hold circuit is digitized using on-chip 10-bit asynchronous column SAR ADCs. Two readout interfaces are available, 400 MHz LVDS and 50 MHz SPI. Total current consumption is 31 mA from a 1.8 V power supply in the SPI mode.