At the heart of Abancens’ team’s detector, which is called a scintillating bolometer and resembles a prop from The Golden Compass, is a crystal so pure it can conduct the energy ostensibly generated when a particle of dark matter strikes the nucleus of one of its atoms.
To prevent interference by cosmic rays, the bolometer is sheathed in lead and kept underground, under half a mile of rock. It’s also frozen to near-absolute zero, the temperature at which all motion stops. At the edge of absolute zero, it’s possible to measure expected changes of a few millionths of a degree Fahrenheit.
Researchers like Abancens call this “a high heat signal.”
As described in a paper published in the August Optical Materials and released online Friday, the bolometer is currently able to distinguish between the vibrations produced by trembling nuclei and spinning electrons. Abancens said it could be operational in five years.