Development of gamma-type energy filtering TEM

A new energy-filter is developed to improve image resolution and enhance the contrast of transmission electron microscopic (TEM) images. The filter consists of two sector magnetic fields and is built into a TEM column, Electrons travel through the filter following gamma-shape trajectories. Electrons in a specific range of energies are selected and focused to produce an image, The energy filter was incorporated into a TEM for observation of unstained biological specimens, With a 1-mu m thick specimen, zero-loss electrons produce a sharper, or less chromatic-aberration image compared with that of a conventional TEM, Meanwhile, with a thin specimen less than 0.1 mu m thick, around 250 eV-loss electrons produce a sharp image while zero-loss electrons do not, Observations show that a TEM equipped with the energy filter is useful for microscopy of fine structures of biological specimens under natural conditions.