| Title: |
Reflection imaging with a helium zone plate microscope |
| Authors: |
Flatabø, Ranveig, Eder, Sabrina D., Reisinger, Thomas, Bracco, Gianangelo, Baltzer, Peter, Samelin, Björn, Holst, Bodil |
| Publication Year: |
2023 |
| Collection: |
Physics (Other) |
| Subject Terms: |
Physics - Instrumentation and Detectors |
| More Details: |
Neutral helium atom microscopy is a novel microscopy technique that offers strictly surface-sensitive, non-destructive imaging. Several experiments have been published in recent years where images are obtained by scanning a helium beam spot across a surface and recording the variation in scattered intensity at a fixed total scattering angle $\theta_{sd}$ and fixed incident angle $\theta_{i}$ relative to the overall surface normal. These experiments used a spot obtained by collimating the beam (referred to as helium pinhole microscopy). Alternatively, a beam spot can be created by focusing the beam with an atom optical element. However up till now imaging with a focused helium beam (referred to as helium zone plate microscopy) has only been demonstrated in transmission. Here we present the first reflection images obtained with a focused helium beam. Images are obtained with a spot size (FWHM) down to 4.7 $\mu$m $\pm$ 0.5 $\mu$m, and we demonstrate focusing down to a spot size of about 1 $\mu$m. Furthermore, we present the first experiments measuring the scattering distribution from a focused helium beam spot. The experiments are done by varying the incoming beam angle $\theta_{i}$ while keeping the beam-detector angle $\theta_{sd}$ and the point where the beam spot hits the surface fixed - in essence, a microscopy scale realization of a standard helium atom scattering experiment. Our experiments are done using an electron bombardment detector with adjustable signal accumulation, developed particularly for helium microscopy.
Comment: 20 pages, 7 figures |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2308.11749 |
| Accession Number: |
edsarx.2308.11749 |
| Database: |
arXiv |
