We report on an improved test of the Universality of Free Fall using a rubidium-potassium dual-species matter wave interferometer. We describe our apparatus and detail challenges and solutions relevant when operating a potassium interferometer, as well as systematic effects affecting our measurement. Our determination of the Eotvos ratio yields $eta_{,text{Rb,K}}=-1.9times10^{-7}$ with a combined standard uncertainty of $sigma_eta=3.2times10^{-7}$.
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