Bulletin Spring‧Summer 2001

Peking University established its physics teaching laboratory, Chen Jia'er was transferred there and given the responsibility of founding the first nuclear physics teaching laboratory in China. In 1959, Chen Jia'er led the laboratory in designing and constructing the first betatron and sector- focussed isochronous cyclotron, beginning a distinguished career i n accelerator physics. In 1963, Chen Jia'er was sent to Britain for further studies. There he worked under Prof. Wilkinson of Oxford University and Prof. Lawson o f the Rutherford Laboratory, in particular studying the central region in isochronous cyclotrons. He analysed, he calculated, he simulated, he pondered; in the end, he fully understood the mechanism leading to beam attenuation, and was thus able to triple the beam transport efficiency. Moreover, he established experimentally the existence of the gap resonance, and developed an ingenious way to damp the resonance. This brilliant achievement was recognized internationally. He returned to China in 1966, but his research was interrupted by the Cultural Revolution. In 1982, Prof. Yang Chen Ning arranged fo r Chen Jia'er to go to the State University of New York at Stony Brook, to take up the task of designing and building the beam pulsing system in Stony Brook's superconducting linear accelerator. Chen Jia'er was able to use to advantage the expertise developed in his own accelerator research i n the 1970s. His research results were developed into a specialized software for controlling the accelerator and its beam transport system. With this development, accelerator operation became accurate, practical, and convenient. The mode of operation, now called the Chen mode, has been in use at Stony Brook since, essentially in the original form. Chen Jia'er returned to Beijing in 1984, and was appointed vice-president of Peking University, with responsibility fo r research and development. He emphasized basic research, applied research, and technological innovations as a trinity in synergy. The policy paid off in rapid advancements for Peking University. Even with the heavy burden of university administration and community service, Chen Jia'er did not give up his research. He led the design and construction of the 4.5 M V electrostatic accelerator. Commissioned in 1990, this accelerator fille d a major gap in monochromatic neutron facilities in China, especially in the energy ranges 3.5-7 MeV and 16-20 MeV This accelerator also laid the foundation for the neutron and fission laboratory in Peking University. In recent years, Chen Jia'er led the design of accelerator mass spectrographs. As principal investigator for the national key 'Xia-Shang-Zhou Project', he used physical techniques to date ancient artefacts, to accuracies of 30-40 years. No more than two or three laboratories worldwide can claim such precision. More recently he suggested and then demonstrated experimentally the feasibility of simultaneously accelerating positive and negative oxygen ions in one structure, and as a result was able to increase significantly the beam current and RF efficiency in the RFQ cavity; the result moreover opened the way to the implantation into experimental samples of two species of ions in any given ratio. This achievement was the first of its kind in the world. Other accomplishments include his work on microwave niobium superconducting accelerators. In August 1996, Chen Jia'er was appointed by the State Council as president of Peking University. During his presidency, he made major contribution s in leading the University's development, and raised its profile in research. With a venerable tradition of 'Patriotism, Progress, Democracy and Science', Peking University takes up the mission of embracing the best of the past in order to build the best of the future. In 1998, under President Chen's leadership, Peking University celebrated its centenary. True to its motto o f Diligence, Rigour, Honesty and Creativity', clear in its vision of 'Carrying on Traditions, Strengthening Teaching and Researches, Meeting the Challenges of the Future and Making Progress', Peking University went from strength to strength. In his presidential address at the University's centenary, Chen Jia'er set out his vision The 56th Congregation for the Conferment of Degrees 41