  We report on the experimental doping of a $^{87}$Rubidium (Rb) Bose-Einstein
condensate (BEC) with individual neutral $^{133}$Cesium (Cs) atoms. We discuss
the experimental tools and procedures to facilitate Cs-Rb interaction. First,
we use degenerate Raman side-band cooling of the impurities to enhance the
immersion efficiency for the impurity in the quantum gas. We identify the
immersed fraction of Cs impurities from the thermalization of Cs atoms upon
impinging on a BEC, where elastic collisions lead to a localization of Cs atoms
in the Rb cloud. Second, further enhancement of the immersion probability is
obtained by localizing the Cs atoms in a species-selective optical lattice and
subsequent transport into the Rb cloud. Here, impurity-BEC interaction is
monitored by position and time resolved three-body loss of Cs impurities
immersed into the BEC. This combination of experimental methods allows for the
controlled doping of a BEC with neutral impurity atoms, paving the way to
impurity aided probing and coherent impurity-quantum bath interaction.
