Sensors for gravity and exotic forces based on single electron transistors (SET)

This proposed effort intends to advance the state of instrumentation in such a way as to address several needs in the field of high energy physics (HEP), while also developing a technology that is applicable outside of HEP. Development of a next-generation, monolithic CMOS imager sensor (CIS) for collider experiments is the primary focus of the first phase, promising smaller pixels, radiation hardness, less material, and more complex circuitry within the pixel matrix and in the end-of-column logic than is found in current approaches. A secondary goal, which is also of great interest, is to provide a novel path to 4D tracking by combining very fast charge collection (on the order of 10ps) with low-noise and high-bandwidth front-end transistors, which would obviate the need to include an LGAD-like structure via a monolithic or hybrid approach. Additionally, this project will enable the exploration of the possibility to use non-ionizing sensing mechanisms, such as magnetic or quantum surface-acoustic wave (SAW) or capacitive, with this low-noise, fast circuitry to enable searches for short-distance gravity, exotic forces, as well as the study of the behavior of geometrically constrained vacuum. The proposed image sensor will be developed in the GlobalFoundries 22nm full-depletion, silicon-on- insulator (SoI) CMOS technology, which provides several key attributes: sensitivity to single electron signals, extremely high transistor density, ability to operate over a wide temperature range from below 4K to above ambient, incorporation of charge qubits at 4K, radiation tolerance due to device dimensions and SoI, access to an extensive set of diffusion options in the bulk wafer, and high bandwidth and time resolution. Equal1 has extensive experience designing in this CMOS process and has built sophisticated, system-on- chip devices, which can operate at temperatures down to 4K. Equal1 has also modeled, designed, and fabricated systems with hundreds of quantum wells that can act as charge qubits. These qubits can have their potentials modulated to control the location of single electrons. SLAC National Accelerator Laboratory, as subawardee, will collaborate with Equal1 on this research and will actively participate in the R&D efforts through sensor modeling, circuit design, radiation testing, and radiation hardness measurements.