Capturing all transmitted electrons allows quantitative measurement of a material’s properties, such as internal electric and magnetic fields, which are important for use of the material in memory and electronics applications. A research group at Cornell University, Ithaca, NY, has developed and tested a new detector for electron microscopes that enables quantitative measurements of electric and magnetic fields from micrometers down to atomic resolution.

The device is an adaptation of existing solid-state X-ray detector technology, now modified to function as a high-speed, high-dynamic-range electron diffraction camera. Dynamic range denotes the maximum range of signals that can be detected by a pixel. The resulting electron microscope pixel array detector records an image frame in under a millisecond, and can detect from 1 to 1 million primary electrons per pixel per image frame. This is 1000 times the dynamic range, and 100 times the speed of conventional electron image sensors.

The electron microscope pixel array detector can record the entire unsaturated diffraction pattern in scanning mode. It can simultaneously capture bright field, dark field, and phase contrast information, as well as analyze the full scattering distribution, opening the way for new multichannel imaging modes.