Figure 1
From: Taxonomy through the lens of neutral helium microscopy
Schematic diagram (not to scale) illustrating the path of helium through the SHeM. The neutral helium atom beam generated by the free-jet expansion is progressively collimated by the skimmer and pinhole apertures, resulting in a pencil beam that strikes the sample surface. The intensity of backscattered helium atoms passing through the detector aperture (located to collect specular reflections) is recorded as the sample is rastered in two dimensions underneath the beam (see red arrows). Insets show an illustrative example of image formation in the SHeM, highlighting the effects of both occlusion and projection distortion by means of a simple geometric sample. The final produced SHeM micrograph of a 3D-printed analogue of the sample is also shown for completeness. Scale bar 500 μm, 2.6 seconds dwell per pixel.
