An electronic image drift compensator for electron microscopy

Image drift frequently occurs when temperature-controlled specimen holders are used or when there is a malfunction of the electron microscope. A simple circuit is presented which supplies a noise-free linear ramp of increasing or decreasing current suitable for manual drift compensation. It has been tested extensively with several side-entry cold stages in a Philips EM420 electron microscope equipped with a low-dose kit. The compensator does not interfere with the use of the low-dose kit and requires no modifications to the microscope.