Measurement results on capacitively coupled particle detector with PHOTON readout chip

A sensor chip for a capacitively coupled pixel detector (CCPD53) has been designed and produced in a 180 nm high voltage CMOS (HVCMOS) technology on a high resistivity wafer with deep p-well option. Capacitively coupled pixel detectors are a simple and low-cost alternative to classical hybrid detectors. They rely on capacitive signal transmission between the sensor chip and the readout chip. A pixel detector with small pixel size can be made without small pitch bumps. The CCPD53 sensor chip contains a pixel matrix of 64 × 40 pixels, each 25 μm × 50 μm in size. The digital output signals of a group of 16 pixels are encoded and the 8-bit output is connected to signal transmission pads arranged with pitch of 50 μm. The pad geometry has been chosen in a way to fit the geometry of the pixel readout ASIC developed by RD53 collaboration at CERN. The PHOTON readout chip has been implemented in the UMC 180 nm CMOS technology. It allows counting and integration of charge signals. The chip consists of a matrix of 32 × 30 identical square pixels with 150 μm × 150 μm size. In this paper the sensor and the readout chip will be described and the measurement results presented.