CAREER: Optical Single Atom Detection for Nuclear Astrophysics

Michigan State University, East Lansing MI

Investigators

Abstract

This award supports the development, construction, and commissioning of an optical microscope capable of imaging individual atoms that are captured inside a thin film of frozen neon. Initially, this single atom microscope will capture and count the number of magnesium atoms produced in collisions of neon and helium atoms. Detailed measurements of these rare collisions will help explain the origin and abundance of copper, silver, and other heavy chemical elements. Because the single atom microscope will increase the sensitivity of these types of measurements by at least a factor of one hundred, laboratory experiments that mimic the conditions inside of stars where these elements are produced will be possible for the first time. In parallel, the PI will develop a modular planetarium program that describes how the chemical elements are formed inside of stars. These modules will be presented within the context of a virtual tour of the National Superconducting Cyclotron Laboratory, which emphasizes how research being conducted at the Lab impacts our understanding of this process and how this research is beneficial to society. The primary research goal of this project is to develop and commission a single atom microscope for measuring rare nuclear reactions that are relevant for nuclear astrophysics. The recoil products will be captured within the noble gas solid and then optically detected using resonant laser excitation and single photon detectors. A single atom microscope designed for magnesium, when coupled with a recoil separator, would allow for measurements of neon-helium nuclear fusion reactions with at least a hundred fold improvement in sensitivity. These reactions play a key role in the production of neutrons that drives the slow neutron capture process (s-process) inside of massive stars, which is responsible for the creation of about half of the heavy elements between mass 60 and 90 including copper and silver. Steps for this project include demonstrating optical single atom detection of ytterbium in solid neon, calibrating the efficiency, sensitivity, and selectivity of the technique, and finally building and commissioning a single atom microscope for measuring the nuclear reactions that produce magnesium atoms. Critical steps include a detailed understanding of the optical backgrounds produced by impurities in the various optical components, optical spectroscopy of ytterbium and magnesium in solid noble gases, and the design of a high light collection efficiency diffraction-limited optical imaging system.