Studies and Design of the ECAL (CMS) Cooling System

The Electromagnetic CALorimeter (ECAL) sub-detector for the CMS experiment has to achieve very tight requirements in terms of temperature stability. The CV group is now involved in the design of a cooling system for ECAL. The status and the content of the work which has been done will be explained. The theoretical studies which helped to understand the ECAL thermal behaviour and the efficiency of the hydraulic network in charge of the cooling will first be briefly presented. Moreover, it will be shown how these studies helped to improve the cooling design inside ECAL. A proposal for an external cooling system of ECAL will be presented as well. Finally, experimental thermal tests, which are planned for April 2000 on a prototype corresponding to a part of ECAL, will be described. These tests aim to check the technical solutions which can be applied in the context of the real ECAL detector.