CO2 cooling for particle physics detectors

A good cooling system is of crucial importance for particle and radiation detector systems that are used in elementary particle physics. In addition to the "normal" design considerations for a cooling system, the systems used in particle detectors are subject to additional unusual constraints. At the Dutch institute for sub-atomic physics - Nikhef - we have developed a technique for cooling particle physics detectors with CO2 (2-Phase Accumulator Controlled Loop or 2PACL). The LHCb experiment at CERN uses this technique successfully to cool a silicon strip detector with a power of 2kW. The coolant temperature can be set between +8°C and -35°C while the temperature fluctuations are well below 0.1°C. In this paper we will give an overview of the requirements for cooling (silicon) detectors in particle physics. We will explain the 2PACL technique we have developed for CO2 cooling and we will show the results obtained with the LHCb experiment at CERN. In addition we will give preliminary results on the ongoing research on heat transfer and gear pump performance for the development of CO2 cooling systems for the next generation detectors