Thermofluidynamic numerical simulation of microchip cooling devices

NA62 is a particle physics experiment that investigates new physics at CERN SPS accelerator. The aim of this experiment is to measure the kaon decay 𝑘+ → 𝜋+𝜈𝜈̅ in order to compare the experimental data with the Standard Model theory. Time, direction, and momentum of the incoming kaon beam are accurately recorded by the GTK spectrometer. The GTK is located into a vacuum chamber and a very low material budget is required to minimize beam interactions. The readout electronics dissipate a lot of thermal power that must be managed by an efficient cooling system in order to keep the temperature of the silicon pixel tracking detectors below 5°C. Indeed, it has been observed that it is possible to reduce maintenance operations and guarantee high performance of the detectors by keeping the temperature below the limit. The goal is achieved by implementing an innovative microchannel heat sink called “Cooling Plate”. Microfabrication techniques are explored to understand how microchannels are etched into the thin silicon wafer and how they are bonded on top. CFD simulations are performed to analyze the thermofluidynamic behavior of the system and empirical tests are carried out to validate the numerical solutions and assess the operating conditions of failure. Furthermore, two alternative updated layouts of the cooling system with zero material budget are proposed. CFD simulations show the best solution taking the first steps towards the new configuration of the GTK heat sink, called “Cooling Frame”.