Accelerator-Electron Microscope Interface System at Wuhan University*

• 作 者: M.Li[1]D.J.Fu[1]J.R.Liu[2]L.P.Guo[1]B.Song[1]C.S.Liu[1]M.S.Ye[1]Y.F.Yu[1]S.B.Yang[1]Y.G.Peng[1]X.J.Fan[1]
• 机 构: Accelerator Laboratory,Wuhan University,Wuhan 430072,China
• 出 处: 第三届全国粒子加速器技术学术交流会
• 发表日期: 2007年期

We report on the establishment of an accelerator-transmission electron microscope (TEM) interface system and preliminary results of in situ observation of micro structural change induced by ion irradiation. The accelerator-TEM interface, the first of its kind in China, consists of a 2×1.7 MV tandem accelerator, a 200 kV implanter, and a 200 keV TEM, linked together by using a home-made beam transmission system. Long transmission pipe and separated pumping were designed so that the mechanical vibration of the accelerator system could be effectively absorbed or isolated before the ion beam reaches the TEM chamber. In addition, a Rutherford backscattering/channeling chamber was installed between the accelerators and TEM. The interface system has been tested with ions of several gas elements. For 115 keV N+ we observed an ion current of 180 nA at the entrance of the TEM sample chamber. The sample stage was tilted to 52°. We have succeeded in observing TEM image and diffraction patterns not only in situ, but also real time for samples irradiated by the low-energy light ions. For Si irradiated by N+ ions, a clear change from single crystal to polycrystal and to amorphous structure has been observed with the increase of the ion flux.