The cooling box offers space for four CMS silicon modules.
The temperature within the volume that contains the modules is adjusted by use of four water cooled, high-performance Peltier elements. To lower the humidity, Nitrogen is provided to the cooling box through two flow regulators - one with a high flow rate and one with a low flow rate. The first is only used at the beginning of the test while the second is constantly open during the test to maintain a low humidity in the cooling box.
The Peltier elements and the N2 flow regulators are connected to controller channels of a "JUMO Imago 500" process and program controller.
The temperature is measured with a Platinum resistance thermometer (Pt-100) connected to the controller. Two program channels are allocated to regulate either heating or cooling. The communication between the controller and the PC is established with an RS422/485 serial interface (using Modbus protocol).