Frank is widely recognized as one of the few authorities in the field of very low-background, low-counting rate experiments. More recently, Frank played a crucial role in the start of two dark matter searches: the DarkSide program for searches with underground argon and the SABRE program for searches with sodium iodide detectors in an active anti-coincidence veto. Frank’s contributions were crucial to establish the technology of DarkSide, a liquid argon time projection chamber, as a credible candidate for large-scale dark matter searches. Drawing on his expertise in nuclear physics and on organic liquid scintillator, he proposed, designed, and developed the most efficient veto detector for dark matter experiments, based on an organic liquid scintillator heavily doped in boron. Thanks to the success of its veto, DarkSide-50 is the only experiment operating with zero background in the search for dark matter with mass above 50 GeV/c2 and has the best exclusion limits for the search of dark matter with mass below 8 GeV/c2. Frank is now deeply involved in developing the SABRE program to verify the only claim for detection of dark matter stemming from the results of the DAMA/LIBRA program, and is leading a very promising effort to develop sodium iodide detectors with the ultra-low radioactive background.

Frank is a dedicated teacher and inspiring mentor. Between 1996 and 2012, he guided six Princeton graduate students’ Ph.D. dissertations on the Borexino Solar Neutrino Experiment and mentored six postdoctoral students. Frank has fostered talent and offered opportunities, physics insight, and career advice to a diverse group of students, one of whom said, “All the nuclear physics I know I picked up over the years from him.” Most of Frank’s doctoral students and postdocs have continued to successful careers in physics, with faculty positions or prestigious fellowships (depending on seniority) and high visibility in the areas of astroparticle physics and gravitational wave detectors.