Foreword

This special issue of Ultramicroscopy contains a selection of the invited and contributed papers that were presented at the Workshop entitled "Materials Science Opportunities for Field Emission Electron Sources", held at the SunBurst Hotel, Scottsdale, Arizona, 5-8 January 1994. This Workshop, attended by about 75 people, was the last in the series of annual meetings sponsored by the NSF-supported Center for High Resolution Electron Microscopy (CHREM) in the Center for Solid State Science at Arizona State University. These workshops have been part of the ongoing educational mission of the Center. Their intent has been to provide a forum for presentation and discussion of subjects of topical interest, thereby enhancing the awareness of the possibilities for electron microscopy applica- tions in the broader materials science community.

In recent years, the commercial development of reliable field emission guns (FEGs) has lead to the general availability of higher-voltage, FEG-based electron microscopes. The objective of this particular meeting was to focus upon the gamut of opportunities for investigations in materials science that might become possible as a result of their enhanced performance. Experts in X-ray microanalysis, electron-energy-loss spectroscopy, microdiffrac- tion and electron holography were invited to review latest applications and to discuss future possibilities for further development. Representatives of microscope manufacturers involved with FEGs attended the meeting and also participated actively in discussion. Contributed papers from other FEG users amply demonstrated the additional benefits that accrued from proper utilization of these instruments.

It became abundantly clear during the course of the Workshop that the FEG microscopes should prove to be of great value to those workers interested in combined microstructural and microchemical analysis. Nevertheless, scope seemed to exist for further improvements. Long- term stability and improved detector efficiency for X-ray mapping, better airlock vacuums and improved sample exchange mechanisms, and increased data handling capabilities, were among the topics mentioned as frustrations by different users. There was general consensus that further evolution of the FEG-SEM and (S)-TEM instruments was still highly desirable.

David J. Smith Tempe, Arizona