The Mainz Microtron (MAMI) is an electron accelerator at the Institute for Nuclear Physics in Mainz, that provides beam energies of up to 1.6 GeV. With its narrow beam profile, quasi continuous stream of particles and beam currents of up to 100 $\mu$A it is well suited for diverse test beam applications. One of them is the high rate testing of detector prototypes.
The talk discusses tests that have been conducted with MuPix8 sensor prototypes during a beam time in August 2018. Preliminary results focusing on the dependency of the detection efficiency on the particle rate will be presented. This is especially relevant for the envisaged usage of this sensor type in the P2 parity violating electron scattering experiment at the new Mainz Energy-recovering Superconducting Accelerator (MESA).