Thermal design and tests for the CMS HCAL readout box

A method is necessary to cool the electronics contained in the readout boxes for the CMS HCAL. The electronics to pre-amplify and digitize signals from the optical detectors will generate a large amount of heat that must be removed from the CMS HCAL system. To accomplish this a thermal management system has been designed that uses metallic extrusions, liquid coolant, and thermal foam to transfer the heat from the electronics to the exterior cooling system. Because the electronics are difficult to access throughout the life of the experiment, the temperature must be kept low to extend life expectancy. In order to test the concepts before the final design is implemented a thermal test station was built. Several methods to are under study to determine the best method of making the thermal routing from source of the heat to the liquid for heat removal. The test bed for this evaluation and methods to monitor the electronics temperature in situ will be discussed. 3 Refs.