Deep inside the ATLAS detector, like in a giant thermos, liquid argon sloshes — a transparent liquid at minus 184 degrees Celsius. When a particle flies through it, a weak electrical signal is born, like a quiet splash. A new chip, ALFE2, helps to hear it — a tiny microchip with four amplification channels. Each channel works like a musical amplifier with two volume knobs, covering both whispers and shouts.
To test 80,000 such chips, engineers built a robot — an automated station that methodically, like a factory assembly line, tests each microchip. By September 2025, the robot had examined more than a tenth of the entire batch. It turned out that over 85% of chips pass strict inspection on the first try, as if out of a hundred assembled bicycles, only fifteen needed spoke tightening. The chips were also tested for radiation hardness: irradiation did not spoil their performance, and rare glitches from cosmic particles are predictable — no more than five per day for the whole detector. Thus ALFE2 is preparing to listen to the symphony of collisions at the Large Hadron Collider for years without losing its hearing.
Liquid argon is so transparent that you could read a newspaper through a meter-thick layer, but in the detector it works as an ideal medium for detecting charged particles: they knock out electrons, creating a measurable current.