北京正负电子对撞机重大改造工程通过国家竣工验收

北京正负电子对撞机重大改造工程(简称BEPCII)是我国"十一五"重大科学工程,是目前重大科学工程中最具挑战性和创新性的项目之一,总投资6.4亿元,工期5年,由中国科学院高能物理研究所承担建设任务。工程于2004年初动工,2008年7月完成建设任务,2009年5月对撞机的主要性能参数亮度在束流能量1.89GeV能量下达3.21×1032cm-2s-1,达到设计指标,为改造前的30多倍,是此前该能区对撞机亮度世界纪录的4倍以上。BEPCII工程按进度、按指标、按预算、高质量地完成了各项建设任务,并于2009年7月17日顺利通过国家验收。BEPCII是一台粲物理能区国际领先的对撞机和高性能的兼用同步辐射装置,它的建成成为国际同类装置建设的一个范例,是中国高能物理发展的又一个里程碑。BEPCII试运行期间,北京谱仪III共采集到一亿多ψ(2S)和两亿多J/ψ事例,是目前世界上最大的数据样本,并已取得了初步的物理结果。BEPCII建成并投入运行,有望在今后多年里,不断取得重大物理成果,进一步保持和加强我国在粲物理研究领域的国际领先地位。

Major Upgrade of the Beijing Electron-Positron Collider

The major upgrade of the Beijing Electron-Positron Collider（BEPCII）is one of the state key scientific projects during the eleventh five-year plan period,which is one of the most challenging and innovative mega-science projects.The Institute of High Energy Physics,Chinese Academy of Sciences,took the responsibility of this 640 MRMB budgeted and 5-year scheduled project.The construction of the project started in the beginning of 2004 and completed in July 2008.In May 2009,the luminosity of BEPCII reached 3.21×1032cm-2s-1 at the beam energy of 1.89 GeV,which is more than 30 times higher in comparison to the value before the upgrade and more than 4 times of the world record achieved before at this energy region.With the five-year efforts,the project has completed on its technical specifications,the planned schedule as well as the specified budget,and passed state assessment in July 2009.As a result,BEPCII has become a world leading collider in charm physics as well as a high performance synchrotron radiation facility.In the meantime,construction of BEPCII is regarded as a good example among the kindred facilities in the world.The successful completion of the BEPCII project is a significant milestone for the development of high energy physics in China.During its test operation,about 100M ψ（2S）and 200M J/ψ events were collected by BESIII detector as the largest data samples in the world,with which some significant results have been obtained.It is expected that important achievements will be obtained in the coming years and China＇s leading position in charm physics research will be well retained and extended.