Building a Single Atom Microscope for Nuclear Astrophysics

The primary research goal of this project is to develop a new technique of optical single atom detection to measure rare nuclear reactions at low energies. The $^{22}$Ne($\alpha$,$n$)$^{25}$Mg reaction is of particular interest, as it is thought to be a primary source of neutrons in the the s-process of massive stars. Nuclear reaction products are captured in a cryogenically frozen film of noble gas, which can contain a variety of guest atoms. These solids are ideal to use because they are optically transparent and simple to grow and purify. The sample is illuminated by laser light and imaged to identify fluorescing atoms. The atomic transitions of captured atoms indicate which atoms are present; only atoms which are excited at the laser wavelength will fluoresce. This offers high selectivity during experiments. We began development with Yb, a very bright guest atom, being embedded in a host of solid neon in order to study the optical properties necessary for single atom detection. In addition, we study background effects from the laser exciting contaminants in our substrates. We present data that indicates the efficiency with which we can excite and collect fluorescence light with our apparatus, and use it to propose a strategy for the development of Mg single atom detection.