ATLAS New Small Wheel Project - Front-End Board Cooling

For the New Small Wheel (NSW) project the innermost end-cap of the ATLAS muon spectrometer will be replaced. This part of the muon tracking system will use the sTGC and Micromegas detector technologies. The high density of the readout channels of both detector installations results in a high density of the Front-End readout boards (FEBs). To extend the service time of the FEBs their cooling is necessary. To achieve this goal, an approach that enables FEB cooling with a combination of custom design aluminium plates and heat conducting gap pad was developed and studied. Furthermore, a method for the heat transfer from the transceivers, which are located on the FEB side opposite to the cooling installations, was developed. Four types of measurements were executed to test applicability of both cooling solutions under the NSW cooling system constraints. The presentation focuses on the cooling test results of the MMFE-8 production board and L1DDC transceivers. The constraints of each task are described and test results of the implemented solution are discussed.