The electronic ground support equipment for the silicon tracker cooling system of the AMS-02 experiment

AMS-02 is a space experiment that will perform cosmic ray studies on board of the international space station starting from July 2009. This paper describes the design and production of electronic ground support equipment (EGSE) that emulates the silicon tracker cooling system in the AMS-02 apparatus. This emulator is needed in order to test the control electronics of the cooling system without the cooling system itself. The cooling system will be assembled and integrated separately and with a different schedule. Using the EGSE, with a proper emulation software, it will also be possible to simulate the behavior of the cooling system in space. The tracker cooling system includes a set of different sensors and actuators which are necessary for bringing the tracker detector to a uniform temperature at which it can operate properly. The sensors include: Pt1000 thermistors, semiconductor thermal sensors, differential and absolute pressure sensors, and pump rotational speed sensors. The actuators are: resistive heaters, Peltier heat pumps and liquid pumps. The EGSE should simulate the behavior of all these sensors and actuators. This means that it must generate the same signals from the electrical point of view but also its global behavior, namely the response to any internal and external condition change should be the same as the actual tracker cooling system. In order to achieve this performance appropriate software that includes the simulated response of the tracker cooling system will be developed. The EGSE has been developed in three phases: in phase 1 we emulated the electrical behavior of each sensor or actuator as a single unit, in phase 2 we integrated those sensors in a single unit and we added a USB computer interface and basic control software. In phase 3 we will develop software emulating the behaviour of the entire tracker cooling system.