TA-CON-2017-003

The PANDA experiment will be part of the new FAIR accelerator center at Darmstadt, Germany. It is a fixed target experiment in the antiproton storage ring HESR. Main topics of the PANDA physics program are the search for new and predicted states and the precise measurement of the line shape by the energy scan method. Crucial for these measurements is the precise determination of the luminosity at each energy point for normalization of the data taken.

To determine the luminosity with a precision of better than 3 %, PANDA will implement a tracking device to reconstruct elastically scattered antiprotons near the non interacting antiproton beam. It will consist of four planes of thinned silicon sensors (HV-MAPS) for the reconstruction of the tracks. HV-MAPS (High Voltage Monolithic Active Pixel Sensor) is a pixel sensor combining frontend electronics with the actual sensitive material on one chip. To increase the signal speed and the radiation tolerance a reverse bias voltage of 60 V is applied. The whole detector system will be operated in vacuum in order to reduce the systematic uncertainty due to multiple scattering. In addition the setup has to have a very low material budget. Therefore the 50 µm thick sensors are glued on both sides of a 200 µm CVD diamond. These modules are clamped in a holding and cooling structure.

This presentation will discuss the technical design of the tracking detector for the luminosity measurement and its challenges like cooling, mechanical support structures, differential pumped vacuum system, and the sensors themselves. All topics are completed by existing prototype results.