Mtingwa received a Ford Foundation fellowship in 1980 and took it to Fermilab in Illinois for a one-year postdoctoral position, and became a research physicist there in 1981. In joint work with James Bjorken, an American theoretical physicist who is Emeritus Professor at the Stanford Linear Accelerator Center, he developed a theory of " intrabeam scattering " in particle accelerators. For this work, he was awarded the 2017 Robert R. Wilson Prize for Achievement in the Physics of Particle Accelerators, since that theory "empowered major discoveries in a broad range of disciplines by a wide variety of accelerators, including hadron colliders, damping rings/linear colliders, and low emittance synchrotron light sources. "