The objective is to develop the technique of optical single atom detection in solid noble gases for measuring rare nuclear reactions in the energy range directly relevant for nuclear astrophysics. In particular, the focus is on the 22Ne(α,n)25Mg reaction, which is an important source of neutrons for the s-process. This process is challenging to measure, as intense beams and low background environments are required. The alternative is to catch the product nuclei in a thin solid film of a noble gas and detect it, this has the potential to be highly efficient and highly selective.
Noble gas solids (e.g. Neon) are an attractive medium because they are optically transparent and provide efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Atoms embedded inside of noble gas solids have a fluorescence spectrum that is often significantly shifted from its absorption spectrum. This makes possible the detection of individual fluorescence photons against a background of intense excitation light, which can be suppressed using the appropriate optical filters
The first start is to optically detect single Yb atoms in solid Ne. Yb is an ideal candidate for initial studies because it emits a strong green fluorescence when excited by blue light and it has an atomic structure that very closely resembles that of Mg.
Preliminary work has been done in the doctoral thesis of Chen-Yu Xu (“Studies of neutral Ytterbium atoms in a solid Neon matrix”, University of Chicago, 2015).