Workshop on Development and Application of Slow Positron Beam Techniques
January 5~January 8, 1999
China Center of Advanced Science and Technology (CCAST), Beijing
In order to track the development trends of positron annihilation techniques in the world, probe into the orientation for development of slow positron beam in China and promote the overlap of positron annihilation techniques with materials, especially surface science, a domestic workshop on “Development and Application of Sow Positron Beam Techniques” was held from January 5 to 8, 1999, by China Center of Advanced Science and Technology (CCAST) in Beijing.
Dr Wei Long, of Institute of High Energy Physics (IHEP) organized academic activities of the workshop with contents and discussions focusing on five fields:
--Development trend in the world and scientific bearing of research work on positron annihilation in China as well as the necessity and feasibility of intense beam development in China;
--Scope and prospects for the application of slow positron techniques in materials sciences, and China’s requirements for materials probes;
--Accelerators applying to intense positron beams, and the feasibility, technical conditions and remaining problems of the physical designs for the intense beam in Beijing and Hefei;
--China’s current works on positron spectroscopy, and shared use of technical labor forces and shared utilization of existing spectrum resources;
--Visit of Beijing sodium-22 based slow positron beam line in LNAT (Laboratory of Nuclear Analyses Techniques), BFEL (Beijing Free Electron Laser Facilities), BSRF (Beijing Synchrotron Radiation Facilities), BEPC (Beijing Electro-Positron Collider) Linac and the nuclear physics hall of IHEP.
Academician Ye Minghan and Chen Nengkuan, as well as other experts on nuclear physics method and materials science fields attended the symposium. More than 50 participants are from IHEP, Shanghai Institute of Nuclear Research, Lanzhou Institute of Modern Physics, Lanzhou Institute of Chemical Physics, Chinese Academy of Nuclear Energy Science, Beijing University, Tsinghua University, Beijing University of Science and Technology of China, Wuhan University, Zhongshan University, Sichuan University, Central China University of Science and Engineering and other institutions. Fang Qinxue, director of Physics II Department of National Nature Science Foundation of China (NSFC), and Chen Xunyuan, director of Fundamental Research Department of Chinese Academy of Sciences (CAS), also attended the symposium.
Daily agenda of the workshop includes comprehensive reports, specialized reports, laboratory tour of IHEP and free discussions. Yan Yonglian, deputy director of IHEP, made an introduction to representatives to IHEP’s work orientation, reform and subject developments, Professor Zhang Tianbao and He Yuanjin gave comprehensive reports on positron spectroscopy. Other reports include Proposal of Intense Positron Beam in Beijing (BIP-Beam) and Hefei, surface 2D-ARCAR spectrometer, application of BEPC testing beam and introduction to BFEL Linac.
When visiting labs, Dr. Wang Baoyi of IHEP introduced Beijing Sdium-22 based slow positron beam line to the representatives; stuffs of BFEL briefed on the theory and application of BFEL and the stuffs of BEPC briefed on BEPC testing beam and BSRF beam stations.
After three days reports and discussions, participants of the workshop reached consensus in three aspects:
-- Slow positron beam, as a kind of nuclear probe method, has its own features when being applied to surfaces, interfaces, semiconductor and other materials studies.
-- China is to catch up with the international trends on slow positron beam, and
-- In view that development of accelerator-based intense positron beam has been a trend worldwide, China, with all required qualifications, should start such project as quickly as possible.
-- Moreover, in view of the existing conditions, most participants hope that IHEP should undertake the intense positron beam project.