Testbeam and Laboratory Characterization of CMS 3D Pixel Sensors

ABSTRACT: The pixel detector is the innermost tracking device in CMS, reconstructing interac-tion vertices and charged particle trajectories. The sensors located in the innermost layers of the pixel detector must be upgraded for the ten-fold increase in luminosity expected with the High-Luminosity LHC (HL-LHC) phase. As a possible replacement for planar sensors, 3D silicon tech-nology is under consideration due to its good performance after high radiation fluence. In this paper, we report on pre- and post- irradiation measurements for CMS 3D pixel sensors with dif-ferent electrode configurations. The effects of irradiation on electrical properties, charge collection efficiency, and position resolution of 3D sensors are discussed. Measurements of various test struc-tures for monitoring the fabrication process and studying the bulk and surface properties, such as MOS capacitors, planar and gate-controlled diodes are also presented