MIT team builds new laser spectroscopy system

Ronald Fernando Garcia Ruiz, an assistant professor at the Massachusetts Institute of Technology (MIT), and his team designed and fabricated a new laser spectroscopy system, called Resonant ionization Spectroscopy Experiments (RiSE), for use at the Facility for Rare Isotope Beams (FRIB). RiSE will enable studies on rare isotope atoms and on molecules, which contain rare isotopes, for nuclear structure studies at the existence limit of nuclei and to aid fundamental symmetries tests.

RiSE has been integrated into FRIB’s BEam COoler and LAser spectroscopy (BECOLA) facility for high-sensitive measurements with rare isotopes available as high-quality low-energy beams at FRIB.

RiSE uses a multi-step laser resonant ionization spectroscopy, where the targeted atom/molecule is selectively ionized and detected as a signal of atom-laser resonances. Ions can be detected virtually without background using a common ion detector. The selectivity of resonant laser light and ease of ion detection are key for this highly sensitive measurement. Relevant science information will be deduced from the resonance frequency, and a narrow spectral linewidth laser light will be used to achieve precise frequency determination. The technique is critical to address key nuclei, by determining their properties close to the existence limit of mass and charge, and to study rare isotope molecules that are extremely sensitive to the violation of fundamental symmetries.

“Our group is very excited to be part of FRIB,” said Garcia Ruiz, an MIT faculty member and the principal investigator (PI) for RiSE at MIT and one of the FRIB Visiting Scholar Program for Experimental Science award recipients in 2020. “The RISE experiment, combined with the unique capabilities of FRIB, is going to provide a new chapter in our understanding of nuclei at the extremes of stability, and the use of rare atoms and molecules in fundamental physics.“

The technique used at RiSE combines collinear laser spectroscopy (CLS) and resonance ionization to achieve a much higher sensitivity than CLS alone. “RiSE enhances the existing capability of BECOLA in laser spectroscopy techniques, and enables key experiments to make the most of discovery opportunities FRIB will provide,” said Kei Minamisono, a senior scientist and PI for RiSE at FRIB.

Michigan State University (MSU) operates the Facility for Rare Isotope Beams (FRIB) as a user facility for the U.S. Department of Energy Office of Science (DOE-SC), supporting the mission of the DOE-SC Office of Nuclear Physics. Hosting what is designed to be the most powerful heavy-ion accelerator, FRIB will enable scientists to make discoveries about the properties of rare isotopes in order to better understand the physics of nuclei, nuclear astrophysics, fundamental interactions, and applications for society, including in medicine, homeland security, and industry.

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