A Belle Pixel Vertex Detector Upgrade: Progress and Plans

Future vertex detection at an upgraded KEK-B Factory, already the highest luminosity collider in the world, will require a detector technology capable of withstanding the increased track densities and larger radiation exposures. Near the beam pipe the current silicon strip detectors have projected occupancies in excess of 100%. Recent advancements in deep sub-micron monolithic active pixel sensors look very promising to address this problem. In the context of an upgrade to the Belle vertex detector, the major obstacles to realizing such a device have been concerns about radiation hardness and readout speed. Two prototypes implemented in the TSMC 0.35μm process were developed to address these issues and test results are presented herein. Given the success of these initial prototypes, design concept studies and plans for the next stages of R&D toward a full -sized Pixel Vertex Detector (PVD) are presented. This document is intended as a repository of information and to serve as the basis of a Technical Design Report for a PVD 1.0 system.