Omega filter installed in the 1 MV microscope of Kyushu University

Abstract A 1.25 MV high-voltage electron microscope with a B-type omega filter has been successfully installed at Kyushu University. An image detection chamber has been set inside a concrete block below the ground level without changing the frame structure for anti-vibration. Nearly the same design as that for the 200 kV microscope has been kept for the present omega filter except for its size. A new pre- and post-filter lens system with rotation-free imaging has been designed. Energy resolution, beam shape and stability of the filter have been measured. Some application data have been obtained to demonstrate the performance of the filter.