摘要： The inner drift chamber of the BESIII is encountering serious aging problem after five year's running. For the first layer, the decrease in gas gain is about 26% from 2009 to 2013. The upgrade of the inner tracking detector has become an urgent problem for the BESIII experiment. An inner tracker using CMOS pixel sensors is an important candidate because of its great advantages on spatial resolution and radiation hardness. In order to carry out a Monte Carlo study on the expected performance, a Geant4-based full simulation for the silicon pixel detector has been implemented. The tracking method combining the silicon pixel inner tracker and outer drift chamber has been studied and a preliminary reconstruction software was developed. The Monte Carlo study shows that the performances including momentum resolution, vertex resolution and the tracking efficiency are significantly improved due to the good spatial resolution and moderate material budget of the silicon pixel detector.
摘要：Before charge-coupled device detectors became widely employed in observational astronomy, for more than a hundred years, the main detection method was photography on astronomical glass plates. Recently, in order to preserve these historical data and maintain their usability, the International Astronomical Union has appealed to all countries for global digitization of astronomical plates by developing or adopting advanced digitization technology. Specialized digitizers with high precision and high measuring speed represent key equipment for this task. The Shanghai Astronomical Observatory and the Nishimura Co., Ltd in Japan cooperated between 2013 and 2016 to develop the first Chinese high-precision astronomical plate digitizer, which was then used for complete digitization of all nighttime-observation astronomical plates in China. Then, in 2019–2021, the Shanghai Astronomical Observatory independently developed new models of plate digitizers that enabled countries such as Uzbekistan and Italy to digitize their astronomical plates. Additionally, a new high-precision and multifunction digitizer was also used to digitize valuable microscope slides from the Shanghai Natural History Museum, providing a successful example of crossdomain application of high-precision digitization technology.
摘要： The reconstruction of the tracks of charged particles with high precision is crucial for HEP experiments to
achieve their physics goals. The BESIII drift chamber, which is used as the tracking detector of the BESIII
experiment, has suffered from aging effects resulting in degraded tracking performance after operation for ap-
proximately 15 years. To preserve and enhance the tracking performance of BESIII, one of the proposals is to
add one layer of a thin cylindrical CMOS pixel sensor based on state-of-the-art stitching technology between
the beam pipe and the drift chamber. The improvement in the tracking performance of BESIII with such an
additional pixel detector compared to that with only the existing drift chamber was studied using the modern
common tracking software ACTS , which provides a set of detector-agnostic and highly performant tracking
algorithms that h