Thermal performance of a 61-cell Si-drift detector module with thermoelectric cooler

In this paper, the static thermal behavior of a 61-cell silicon drift detector module is investigated. The influence of thermal conductivity of the case material on the heat flux inside the module is discussed by 3-D simulations. The use of graphite allows an operation with spatial inhomogenities of ⩽1°C in the case parts and leads to a sufficient low sensor temperature level. Experiments with a single-stage thermoelectric cooler and heat sink mounted on top of the module confirm that the temperature of the sensor and electronics as well as the case temperature depend linearly on their power dissipation. A set of equations considering the thermal coupling between sensor and electronics fully describe the dependence of their operating temperatures on sensor and electronics power dissipation, cooling power, and ambient temperature under forced convection. The simulated curves show a very good quantitative agreement with the measured characteristics. At a power dissipation level of 1.25 W, an ambient temperature of 22°C and air velocity of ⩾18 cm/s the sensor can be operated down to 13°C and 9°C with a cooling power of 2.8 and 7 W, respectively. Without cooling fan and cooling power the sensor temperature remains below 35°C.