HREM ALIGNMENT AIDED BY A REAL-TIME DIFFRACTOMETER USING A LIQUID-CRYSTAL PANEL

By using a hi,oh-resolution liquid-crystal panel, a high-performance r eal-time diffractometer is realized. With this diffractometer, a high- precision astigmatism correction can be carried out easily even by a n ovice operator. A coma-free alignment procedure proposed by Zemlin [Ul tramicroscopy 4 (1979) 241] is re-examined in order to take into accou nt the three-fold astigmatism. The accuracy of the coma-free alignment using the real-time diffractometer is similar to that obtained by com puter diffractogram analysis.