News Center

Science Underground: Going to Great Depths

The May 30, 2012 dedication of the Davis Campus of the Sanford Underground Research Facility (SURF), 4,850 feet down in South Dakota’s Homestake Mine, marks the official debut of research dedicated to solving some of the most challenging puzzles in 21st-century science. What is the nature of dark matter? What secrets are mysterious neutrinos still hiding? Shielded from cosmic rays by almost a mile of solid rock overhead, supersensitive experiments at the Sanford Lab’s Davis Campus are searching for the answers.

MAJORANA, the Search for the Most Elusive Neutrino of All

Neutrinos may be even stranger than they seem, if indeed they are the only fermions (particles of matter) that are their own antiparticles. Proof would be a rare form of radioactive decay called neutrinoless double-beta decay, which could only be seen if there’s virtually no background interference. The MAJORANA DEMONSTRATOR now under construction at the Sanford Underground Research Facility in the Black Hills of South Dakota aims to prove these near-perfect conditions can be met.

Where Do the Highest-Energy Cosmic Rays Come From? Probably Not from Gamma-Ray Bursts

Some rare cosmic rays pack an astonishing wallop, with energies prodigiously greater than particles in human-made accelerators like the Large Hadron Collider. Their sources are unknown, but gamma-ray bursts are a favored candidate. If so, they should also produce ultra-high-energy neutrinos. Scientists searching for these with IceCube, the giant neutrino telescope at the South Pole to which Berkeley Lab has made key contributions, have found exactly zero. The mystery deepens.

Announcing the First Results from Daya Bay: Discovery of a New Kind of Neutrino Transformation

The Daya Bay Reactor Neutrino Experiment collaboration has announced a precise measurement of the last of the unsolved neutrino “mixing angles,” which determine how neutrinos oscillate among different types. The ground-breaking collaboration, led by the United States and China and initiated by Berkeley Lab, is the most sensitive reactor neutrino experiment in the world. The results promise new insight into why enough ordinary matter survived after the big bang to form everything visible in the universe.

First Data from Daya Bay: Closing in on a Neutrino Mystery

Berkeley Lab physicists have played a leading role in designing and building the international Daya Bay Reactor Neutrino Experiment in southern China, which has just begun collecting data on the elusive final measurement needed before the masses of the different kinds of neutrinos can be determined.

Daya Bay on the Brink

Within the past few weeks, the Daya Bay Reactor Neutrino Experiment in China has made rapid strides toward completion of the first of three underground experimental halls for collecting data on the last unknown neutrino “mixing angle.” A mini-slide-show looks at the giant underground experiment’s progress.

What Keeps the Earth Cooking?

From the planet’s core to its surface, heat enables Earth’s magnetic field, spreads the sea floor, and keeps continents on the move. Much of the heat is “radiogenic,” from the radioactive decay of elements in the crust and mantle, but how much? By measuring neutrinos from deep in the Earth, Berkeley Lab scientists and their colleagues at Japan’s KamLAND neutrino detector have published the most precise estimate yet of radiogenic heat.

The Daya Bay Neutrino Experiment: On Track to Completion

How much do different kinds of neutrinos weigh? And which kind is the heaviest? The answers could explain why there is more matter than antimatter in the universe, and indeed why there is any matter at all. Clues lie in determining the “mixing angles” at which neutrinos oscillate, one type into another. The Daya Bay Neutrino Experiment, an international collaboration whose U.S. participants are led by Berkeley Lab scientists and engineers, seeks to determine the most elusive mixing angle of them all, called theta one-three. See this interactive photographic tour of the remarkable underground laboratory.

Into the Ice: Completing the IceCube Neutrino Observatory

IceCube, the world’s most sensitive neutrino detector, is now complete. The giant neutrino telescope, buried a mile and a half deep in the Antarctic ice, now has its complete array of 86 strings carrying over 5,000 photodetectors, deployed to search for signs of neutrinos passing through the clear polar ice. The electronics and packaging of the photodetectors, called Digital Optical Modules, were conceived, designed, and tested by Berkeley Lab scientists and engineers.

Wriggling Neutrinos Caught in the Act

The first direct observation of a muon neutrino turning into a tau neutrino at the Gran Sasso underground laboratory in Italy confirms that indeed neutrinos do oscillate among “flavors.” Berkeley Lab’s Kevin Lesko says the result “really nails the neutrino oscillation phenomenon.”