Design and evaluation of EMPIX2, a 100 kfps, high dynamic range pixel detector readout ASIC for electron microscopy

Abstract

EMPIX2 is a novel hybrid pixel detector readout ASIC for electron microscopy with a maximum frame rate of 100 kfps and a very large dynamic range (5 × 105:1). It features 128 × 128 square pixels at a pitch of 150 μm. Adaptive gain switching and charge pump technology are applied to enhance the dynamic range. The pixels can operate in two modes: pulse mode and continuous mode. In pulse mode, ultra-fast gain switching enables a rapid response to pulsed electron sources, making it highly suitable for UEM applications. In continuous mode, the power consumption and dynamic range are optimized for STEM applications. The readout is frame-based, and digital image data is output by 64 pairs of LVDS drivers working in DDR mode at a clock frequency of 400 MHz. A dedicated data acquisition system was developed for the transmission and processing of the image data. Preliminary verification of the readout chip was performed using an on-chip calibration source.