Author: Funahashi, Y.
Paper Title Page
THPWA012 The Development of a New Type of Electron Microscope using Superconducting RF Acceleration 3654
  • N. Higashi
    The University of Tokyo, Graduate School of Science, Tokyo, Japan
  • A. Enomoto, Y. Funahashi, T. Furuya, Y. Kamiya, S. Michizono, M. Nishiwaki, H. Sakai, M. Sawabe, K. Ueno, M. Yamamoto
    KEK, Ibaraki, Japan
  • M. Kuriki
    HU/AdSM, Higashi-Hiroshima, Japan
  • S. Yamashita
    ICEPP, Tokyo, Japan
  We are developing a new type of electron microscope (EM), which adopts RF acceleration in order to exceed the energy limit of DC acceleration used in conventional EMs. It enables us to make a high-voltage EM more compact and to examine thicker specimens, and possibly to get better spatial resolution. Using a superconducting RF cavity, we can operate the EM in CW mode to obtain a beam flux comparable to that in DC mode. Low energy dispersion ΔE/E , e.g. 10-6 or better, is required for good spatial resolution in EMs, while it is usually between 10-3 to 10-4 in accelerators. We have thus designed a special type of cavity that can be excited with the fundamental and second-harmonic frequencies simultaneously; TM010 and TM020. With the two-mode cavity, the energy dispersion of the order of 10-5 would be obtained by modifying the peak of accelerating field to be flattened. As the proof-of-principle of our concept, we are developing the prototype using a 300 keV transmission electron microscope (TEM), to which a new photocathode gun and the two-mode cavity are attached. We have already manufactured the cavity and it is under test, and the gun is under construction.