Congratulations to Lauren Callahan for successfully defending her Doctoral Dissertation on April 4th, 2023. Her thesis titled "ACCELERATOR MASS SPECTROMETRY WITH THE MONICA DETECTOR AT THE ARGONNE GAS-FILLED ANALYZER AND ULTRA-SENSITIVE DETECTION OF 39,42Ar" advised by Professor Philippe Collon, focused on the development, testing and implementation of a new multi-anode, position sensitive gas detector MONICA for use at AGFA at the Argonne National Laboratory ATLAS accelerator facility. Specifically designed for Accelerator Mass Spectrometry of medium-mass radioisotope at ATLAS using the gas-filled magnet isobar separation technique. This detector was also used as part of her thesis for the detection of 39,42Ar as a diagnostic tool for the National Ignition Facility (NIF) fusion work. Lauren is preparing for her next career steps, we wish her all the best in her future endeavors!