Several ab-initio theoretical approaches, which start from “bare” nucleon-nucleon and empirical three-nucleon potentials, are being developed for nuclear physics. These calculations of light nuclei have deepened our understanding of how nuclei are bound, the structure of their wavefunctions, and the importance of three-body forces. However, several aspects of the three-body force are not yet well constrained and require precise experimental measurements. In this work, we focus on inferring lifetimes of excited nuclear states through the slowing down of nuclei in materials, the DSAM (Doppler Shift Attenuation Method). Historically, DSAM measurements in light nuclei gave large uncertainties due to many systematic errors. An improved DSAM technique will be discussed which significantly reduces systematic errors and improves the accuracy of the measurement to a level (<5%) where the electromagnetic matrix elements between excited states can provide useful constraints on modern calculations. Experiments to measure the lifetimes of bound states in ¹⁰Be and ¹⁰C will be presented. The experimental results will be discussed in terms of new ab-initio calculations using a number of realistic forces which explore the sensitivity to three-nucleon potentials.