Radiation Hard Pixel Tracking Sensor for High Luminosity Colliders

In this project we are proposing to develop a radiation hard monolithic active pixel sensor (MAPS) for MIPS tracking in high luminosity Nuclear Physics particle detectors. The performance is estimated to nearly match that of state of the art hybrid sensors. The device will be able to support very high hit rates of 750 MHz/cm2. These devices are suited to cover very large areas very close to the vertex and meet most stringent power and cost constraints. Devices like the proposed one have been demonstrated to survive radiation exposure to >1 Grad and a TID (Total Integrated Dose) >2x1016 neq/cm2 1 MeV neutron equivalent. Although previous generation hybrid pixel detector arrays provide excellent tracking information, their fabrication cost, the comparatively large amount of material from CMOS IC plus detector in the path of a minimum ionizing particle (MIP) plus their high power dissipation could be significantly improved upon with new technology. Except for the innermost tracking layer an improvement for implementation in the next generation of HEP experiments is required. Sensor Creations, Inc. (SCI) has developed a MAPS technology based on an industrial CMOS process using high resistivity silicon, i.e. Si > 6.5 kΩ x cm. Finished 8’’ CMOS wafers are thinned to 50-400 m, and a backside electrode is added to form a vertical PIN photodiode which deliver high speed, low noise performance without a gain enhancing pixel level amplifier. Furthermore, SCI has designed, fabricated and packaged a particle tracking chip based on an “Orthopix” architecture. In phase I, we will: (1) Characterize the radiation hardness of our existing “Orthopix” tracking chip up to a total dose of neq=2*1016/cm2; (2) Design and simulate a new architecture for a new MAPS digital Nuclear Physics sensor based on pixel sub-arrays with resolution of 32x32 pixels; and (3) Design the top-level schematic for the new sensor to be fabricated in phase II. In phase II, we will design and fabricate and test the sensor design in phase I. By the end of the entire program, we will deliver a high speed a monolithic CMOS sensor suitable for particle tracking at the inner layer of the detectors at the Electron Ion Collider (EIC).