LOW-DOSE HIGH-RESOLUTION ELECTRON-MICROSCOPY OF ZEOLITE MATERIALS WITH A SLOW-SCAN CCD CAMERA

We demonstrate the application of a commercially available slow-scan CCD camera to low-dose high-resolution electron microscopy on zeolite materials. A resolution of 2 angstrom has been successfully achieved for both Y-zeolite and ZSM-5. The slow-scan CCD camera offers two important advantages: (1) low readout noise which allows high-resolution images to be recorded with very low beam intensity; (2) digital storage of the CCD images which allows immediate evaluation of recorded image quality using on-line image-processing routines, making the image recording much more efficient. Image processing is essential for retrieving the high-resolution structure information that is often obscured by the noise in a low-dose image.