Thermal influences of the front-end electronics on the alice TPC readout chamber

The Alice time projection chamber (TPC) detector will be operated with a gas mixture of 90% Ne and 10% CO 2 at the electric field of 400 V/cm. Recent studies favor a three-component mixture by adding about 5% N 2 , which will improve the stability of the gas against discharges. These operating parameters lead to a nonsaturated drift velocity for electrons but also impose that all external influences on the drift gas must be reduced to minimum. A problematic influence is the temperature variation, which can lead to local fluctuation in the gas density and therefore directly affects the drift velocity. For the Alice TPC, the aim is to have a temperature stability of 0.1degC over the full drift length (2.5 m). The main heat contribution comes from the readout chambers' front-end electronics and one estimates that a total of 30.2 kW must be removed. In this paper we present the cooling strategies for the TPC and discuss the results of the thermal test setup build for validation