Control of specimen orientation and environment.

Application of electron microscopy in a wide variety of fields of investigation has placed ever-expanding demands on the various components of the instrument. In situ specimen manipulation is one such demand and can often be critical to the success of an experiment. Control of specimen orientation is the most common manipulation, but control of a variety of other physical and chemical parameters may also be important. Temperature, gaseous and/or liquid environment, and mechanical operations are examples. Control and variation of these parameters in a small device (occupying a few cm3) operated in a strong magnetic field inside a vacuum system is often a considerable challenge. This must also be done at extreme stability: at least as good as the resolution limit of the microscope. Optimization of stage performance is too often sacrificed for optical performance or vice versa. The next generation of objective lenses and specimen stages are being designed in concert: an approach which should lead to an improved in situ laboratory, observed with optimum optics.