The purpose of CERN's NA62 experiment is to study kaon decays to enable physicists to check certain predictions in the Standard Model of particle physics. At the heart of the experiment is the NA62 Gigatracker, which is made up of three particle detectors that are cooled to around –20 °C by silicon microfluidics systems supplied by Leti.
The cooling circuit is a network of microcanals just tens of microns deep obtained by plasma etching on 200 mm silicon wafers. A second wafer is bonded (by molecular bonding) to virtually the entire surface of the first wafer and is completely free of any defects that could result in leaks or short circuits. A fluid circulates in the canals to keep the system at its operating temperature. Titanium-nickel-gold metallization was used to weld the capillaries that carry the fluid.
The silicon micro-coolers are up and running on NA62, where they have performed well—some of the coolers have withstood pressure up to several hundred bars. The advance enabled Leti to acquire know-how and earn the trust of CERN that could lead to the development of components for other experiments like the LHCb detector on CERN's main accelerator.