Recently, the installation and commissioning of innerTime-Projection-Chamberupgrade detector (inner TPC, iTPC) were successfully completed at the STAR experiment in Brookhaven National Laboratory (BNL) and and physics data taking started in February 2019. The iTPC upgrade is a Sino-US cooperation project dedicated for RHIC-STAR experiment TPC upgrade. The readout wire chamber of iTPC is a collaborative effort by Shandong University (SDU), University of Science and Technology of China (USTC) and the Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences (CAS). At the recent closeout review for iTPC project by the US Department of Energy, this project was highly recognized by the review committee.iTPC project is another important contribution of High Energy Physics group of Shandong University in the development of large-scale international cooperative experiments after the ATLAS-TGC detector project.
Supported by the Institute of Frontier and Interdisciplinary Science of Shandong University,Professor Xu Qinghua' group started the Multi-Wire Proportional Chamber (MWPC) R&D and prototyping for iTPC project in 2014. The SDUgroup together with USTC and SINAP is responsible for the MWPC production and performance testing for the iTPCupgrade. Professor Xu Qinghua led the Chinese efforts of STAR-iTPC project. In 2016, the first full-size iTPC module was successfully completed. In order to ensure the performance of the mass-produced detectors, the team established a strict batch production process and quality control system. Two out-side reviews with members from domestic and international detector experts were conducted in 2016, which were very helpful for the project. After the mass production started in 2017, the team worked hard in particular when there was some delay by upstream technical and performance issues. Finally, all the detectors were produced with high quality on time by September 2018, which met or exceeded the performance requirements by the STAR experiment. Subsequently, they were transported to the Brookhaven National Laboratory in the United States where the STAR experiment is located. They were then successfully installed at the STAR experiment at the end of 2018 and officially started operation in February this year.
The successful completion of iTPC detectors at Shandong University was highly recognized by the STAR management and experts from the US Department of Energy (DoE). In October 2018, J. Dunlop from physics department of BNL and STAR iTPC project manager F. Videbaek sent a congratulatory letter (attached) after the installation of the detector, congratulating the SDU team for their excellent work. At the recent closeout review by DoE on May 2nd this year, the review panel was impressed by SDU team's work: "High-quality, fully tested MWPC modules that met or exceeded the required performance specifications were delivered to BNL on-time by SDU. SDU should be recognized for this technical achievement as well as for the team's willingness and ability to recover schedule delays caused by upstream technical and performance issues".
The second phase of the Beam Energy Scan at RHIC collider is scheduled to run during 2019-2021. The main physics objective is to study the phase structure of quark matter and search for the possible phase transition critical point. The iTPC upgrade is the critical part of detector upgrade. The TPC is the core detector of the STAR experimental group. It has been successfully operated for more than 20 years and a series of important discoveries were based on TPC, such as the existence of near-perfect fluids, the observation of the heaviest anti-mater nuclei and hyperon' sglobalpolarization.
The STAR collaboration consists of more than 600 researchers from 60 institutionsin14 countries. The STAR-China group includes Fudan University, Huzhou University,Central China Normal University, Tsinghua University, Shandong University, University of Science and Technology of China, Institute of Modern Physics (CAS), Shanghai Institute of Applied Physics(CAS) etc.
The iTPC project in China was supported by the Ministry of Science and Technology of China, National Natural Science Foundation of China, and Shandong University. The team members who made important contributions to the project at SDU include Xu Qinghua, Yang Chi, Zhu Chengguang, Yang Qian, Zhang Shengguo, Li Changyu, Sun Yansheng, Deng Jian, Lu Peng, and Ph.D. students includingShen Fuwang, Wang Shuai, Wang Xu, Kong Fangang, etc.
The link for the news from Brookhaven National Laboratory on the completion of iTPC project:
Written by:Qian Yang
Edited by: Che Huiqing