基于大面积超薄CMOS像素传感器的BESIII内径迹室关键技术研究

BEPCⅡ计划将亮度再提高2-3倍并继续运行十年，这对BESⅢ漂移室内室的长期稳定运行提出挑战，需要对其升级。本申请拟开展新型的大面积超薄硅像素径迹室的关键技术预研，它将通过近年来CMOS半导体工业提供的缝合技术，研制晶圆尺寸的像素传感器。该传感器减薄到一定厚度后可以卷曲形成自支撑，从而能以最简化的支撑结构组装成桶形探测器层，每层具有前所未有的极低物质量，极大提高低动量带电粒子的探测精度和效率。本申请如获支持，我们将研究可缝合的像素传感器设计，研制由其构成的探测器原型机，开发相应的测试电子学和数据获取系统，并通过束流实验验证探测性能。同时，我们还将在BESⅢ软件框架里开展探测器的模拟研究，优化探测器几何设计，挖掘其物理潜力。本项目的开展将为BESⅢ漂移室内室的升级提供可行的技术方案，并为未来对撞机实验的寻迹系统提供崭新的设计思路。

The BEPCII has been planned to run until about 2030 with two- or three-fold increase of luminosity. Hence, the inner chamber of the BESⅢ tracking system will confront severe challenge in the future and an appropriate tracking technology is foreseen to be applied. The proposal will carry out study of a novel tracker consisting of curved wafer-scale ultra-thin silicon pixel sensors. The sensor fabrication will be based on a technology, so called stitching, offered recently by the CMOS semiconductor industry. After thinning, the wafer-scale sensors can be bent naturally, therefore, can be arranged in perfectly cylindrical layers with minimum support structure, featuring an unprecedented low material budget per layer. The consequence would be a significant improvement of the tracking precision and efficiency for charged tracks with low transverse momentum. Should the proposal be approved, we will study the design of pixel sensors capable of stitching, construct a detector prototype with the pixel sensors, develop testing electronics and data acquisition system, and verify detection properties via beam test. In addition, we will perform detector simulation within BESⅢ software framework to study the optimization of detector layout and physics potential with such an inner tracker. Success of the study will provide a feasible engineering design for upgrading the BESⅢ inner tracking chamber and an innovative approach in tracking system design for the future collider experiments.