ISLAMABAD-One of the ways neutrinos can be detected is with large vats filled with liquid argon and wrapped with a complex web of integrated circuitry that can operate in temperatures colder than the average day on Neptune. Industry does not typically use electronics that operate at cryogenic temperatures, so particle physicists have had to engineer their own. A collaboration of several Department of Energy national labs, including Fermilab, has been developing prototypes of the electronics that will ultimately be used in the international Deep Underground Neutrino Experiment, called DUNE, hosted by Fermilab. DUNE will generate an intense beam of neutrinos at Fermilab in Illinois and send it 800 miles through the Earth’s crust to detectors in South Dakota.

Results from the experiment may help scientists understand why there is more matter than antimatter, an imbalance that led to the formation of our universe. DUNE’s neutrino detectors will be massive: a total of four tanks, each as high as a four-story building, will contain a combined 70,000 tons of liquid argon and be situated in a cavern a mile beneath Earth’s surface. Argon occurs naturally as a gas in our atmosphere, and turning it into a liquid entails chilling it to extremely cold temperatures. The atomic nuclei of liquid argon are so densely packed together that some of the famously elusive neutrinos traveling from Fermilab will interact with them, leaving behind tell-tale signs of their passing. The resulting collision produces different particles that scatter in all directions, including electrons, which physicists use to reconstruct the path of the otherwise invisible neutrino. A strong electric field maintained within the detector causes the free electrons to drift toward wires attached to sensitive electronics. As the electrons travel past the wires, they generate small voltage pulses that are recorded by electronics in the liquid-argon chamber. Amplifiers in the chamber then boost the signal by increasing the voltage, after which they are converted to digital data. Finally, the signals collected and digitized across the entire chamber are merged together and sent to computers outside the detector for storage and analysis.