Fueling Discovery

Operating under the harshest conditions on Earth, Analog Devices products are helping astrophysicists see what no one has ever seen before: cosmic neutrinos.

Frozen into place 1.5 miles beneath the Antarctic ice, ADI data converters and amplifiers help enable the world’s largest particle detector—named IceCube—to capture the notoriously elusive neutrinos.

“ADI components are at the heart of detecting neutrino collisions and transferring that information up and out of the ice,” said Michael DuVernois, IceCube Instrumentation Manager at the University of Wisconsin–Madison. “From the beginning, we had a high level of trust that ADI parts would perform in conditions below -40 ºF.”

As the parts couldn’t be replaced once positioned in an ice sheet that moves about 30 feet a year, it was critical to ensure their long-term reliability. “We expect the parts to be operating for another 20 years and the next-generation IceCube will include ADI,” DuVernois said.

Measuring the Immeasurable

Invisible, chargeless and nearly weightless, neutrinos zip through space at light speeds—easily passing through walls and sheets of ice. Building an observatory capable of seeing them took six years and $279 million.

Extreme temperatures, harsh conditions and the sheer size of the detector made the endeavor particularly challenging. However, scientists and engineers from a dozen countries found a way to bore holes deep into the Antarctic icecap. A special drill shot 200 gallons per minute of 190° F water at 1,000 psi to melt 86 openings 1km to 2km deep.

The team then lowered more than 5,000 light-collecting globes the size of basketballs into the holes. These spherical detectors—called digital optical modules (DOMs)—contain high-performance electronics, including sensors that measure the light emitted when neutrinos hit water molecules in the ice. Using ADI converters and amplifiers, the DOMs’ onboard communication system digitizes these signals to protect them as they travel a mile up to the surface.

Ushering in a New Era

Given neutrinos’ elusive nature, the number of particle showers detected by IceCube (28 and counting) surprised even Francis Halzen, the observatory’s principal investigator and physics professor at UW–Madison. 

“We have finally discovered a flux of neutrinos coming from beyond the atmosphere. This is the dawn of a new age of astronomy,” Halzen commented after the discovery, which earned the observatory Physics World magazine’s “2013 Breakthrough of the Year.”

Cosmic neutrinos are expected to shed light on dark matter—the invisible mass that makes up most of the universe—and could unlock the origins of cosmic rays, supernova explosions and other cataclysmic events from which the particles originate. 

In the meantime, IceCube continues to outperform design specifications. It will gather experimental data about particle collisions for another 20 years. 

“This project had so many unique aspects for which no education can prepare you,” said Halzen. “Problems came up and they had to be solved,” he said. “That was the pleasure— helping to solve problems.”