Basic Science

Joint Efforts for Success of ECR Ion Source

In the 13th International Ion Source Conference held in the United States recently, Zhao Hongwei, Associate Director General of the Institute of Modern Physics, CAS, Claude Lyneis, Deputy Director of Nuclear Science Department, US Lawrence Berkeley National Laboratory (LBNL), Daniela Leitner, Director of 88-Inch Cyclotron Department, LBNL and Xie Zuqi, visiting research fellow of the Institute of Modern Physics and a famous Chinese American scholar were granted the Brightness Award in 2009, the highest award in international ion source field, as a commendation for their outstanding achievements in and great contributions to the field of superconducting ECR (Electron Cyclotron Resonance) ion source in the past few years. The ion source research group of the Institute of Modern Physics, headed by Zhao Hongwei, with Xie Zuqi as consultant, successfully developed the high charge state superconducting ECR ion source (SECRAL) with an innovative structure through optimal design and integrated innovation. Unlike traditional ECR ion source magnet structure that has been used for more than 20 years in the world, in this “cold” superconducting magnet structure, the solenoid coils that can produce axial magnetic field are located inside the radial sextupole magnet. This ion source has set several world records for high charge state ion beam intensity under18GHz microwave frequency and 18GHz and 14.5GHz dual-frequency microwave working mode. Recently, it set several world records for high charge state ion beam intensity under 24GHz microwave frequency again, such as 455 microampere Xe27+ and 152 microampere Xe30+. The intensity of these ion beams is much better than that of 28GHz superconducting ECR ion source VENUS of the US Berkeley National Laboratory. The lecture by Zhao Hongwei at the 13th International Ion Source Conference was highly commented by international peers as a special lecture attracting the greatest attention. This again proves that this superconducting ECR ion source developed by the Institute of Modern Physics is one of the best high charge state ECR ion sources in the world. Many famous foreign laboratories have expressed the wish to cooperate with the Institute of Modern Physics and copy or purchase the superconducting ECR ion source developed by them.

More Galaxy Clusters Discovered in Nearby Universe

Dr. Wen Zhonglue and his colleagues from the National Astronomical Observatories of CAS found nearly 40,000 galaxy clusters in the nearby universe from the Sloan Digital Sky Survey (SDSS). The cluster catalog is about three times of previous known 13,000 galaxy clusters. The distribution of galaxy clusters in the universe is expanded from redshift z=0.3 to z=0.6. The paper was recently published in the Astrophysics Journal Supplement Series, with impact factor 13.99. The results have drawn wide attention by colleagues in the world. Compared with the previous largest galaxy cluster sample (maxBCG, 13,823 galaxy clusters), the galaxy clusters catalog found by Wen et al. is much larger and has higher redshift. Such are important data in the research of matter distribution and structure formation of the universe. Also, these galaxy clusters can be targets for the National Large Science Program-- “LAMOST”.

SCM Research of InGaAs/InP APD Structure

Recently, the Applied Physics Letters (Vol.59, 093506) published the achievements in the research of InGaAs/InP avalanche photodiode (APD) structure realized through scanning capacitance microscopy (SCM) by the Shanghai Institute of Technical Physics, CAS. Researchers adopted SCM to study the distribution character of carrier in InGaAs/InP APD structure. Based on this, they detected the polarity reversal effect of differential capacity signal caused by injection of non-equilibrium carrier under optical excitation. No literature and publications on such research of electronic distribution of semiconductor infrared device structure and relevant experiments have ever been found. Moreover, this approach has been applied in technical inspection of III-V group infrared devices and supported another major research projest entitled “single photon detection theory and technology” and the research on components of short-wavelength infrared inGaAs photodetector and someother key projects.