The Carl Zeiss Orion Plus helium ion microscope (HIM) generates a focused beam of helium ions, with a beam energy of 10-35 keV, and raster scans the beam across a sample, inducing the emission of secondary electrons. An image is formed, pixel by pixel, from the emitted secondary electrons in the same way as in a scanning electron microscope (SEM). The larger mass and therefore smaller de Broglie wavelength of helium ions compared to electrons, combined with the extremely small and bright source (courtesy of the atomically sharp tip at which helium atoms are ionised), and the small interaction volume of the beam in the sample enables imaging of surfaces with sub nanometer resolution along with a depth of field up to 10 times larger than in an SEM. Insulating samples can be imaged without a conductive coating by using the integrated electron flood gun to neutralize charge build up. A backscattered ion detector is also available for obtaining images rich in elemental contrast.

The focused beam of ions can also be used to modify samples on the nanometer scale by directly sputtering material in the same way as the Ga focused ion beam. An external pattern generator is available to facilitate the writing of complex patterns using the sub-nm sized probe.