The PANDA-Experiment will be a fixed target experiment at the future FAIR-accelerator center at Darmstadt, Germany. As the experiment is designed for high precision measurements with an antiproton beam, especially in the charm sector of hadron spectroscopy, a precise knowledge of the luminosity is crucial.
The determination of the luminosity will be done by measuring the angular distribution of elastically scattered antiprotons at very small scattering angles between 3 and 8 mrad. Therefore their tracks will measured by four layers of thinned HV-MAPS silicon sensors of 50μm thickness. To minimize the multiple scattering, the measurement is performed in vacuum. As the sensors will dissipate up to 7mW/mm^2, an active cooling is mandatory. To achieve this while maintaining a low material budget, the sensors will be glued on 200 μm thin CVD-diamonds which are clamped in an actively cooled aluminium heatsink outside of the acceptance. An excellent thermal contact to the stainless steel pipe for the coolant is ensured by melting the aluminium around the pipe before machining the heatsink. The poster will present the mechanical design and the cooling system.