MIT physicists claim to have developed a small, tabletop instrument that can identify individual particles down to a single electron emitted from a cloud of radioactive gas. The machine uses magnets to trap electrons inside a magnetic bottle where they give off weak signals that the machine can track over several milliseconds. The scientists operating the particle detector said that the electrons dispelled by the radioactive gas vibrate at a particular baseline frequency that will jump when the electrons collide into an atom of the gas.

MIT physics professor Joe Formaggio explains that an electron colliding with atoms will display its frequency in a step-like pattern, jumping up with each collision. Tech Times also quotes Formaggio as saying, “We can literally image the frequency of the electron, and we see this electron suddenly pop into our radio antenna…Over time, the frequency changes, and actually chirps up. So these electrons are chirping in radio waves.”

This breakthrough is a big step in one of the most maddening of physics mysteries: defining the mass of a neutrino. A neutrino is a type of basic particle that runs rampant throughout the universe and is hard to detect because it doesn’t interact with normal matter in the typical way, but passes straight through it instead. “We have [the mass] cornered, but haven’t measured it yet,” Formaggio says. “The name of the game is to measure the energy of an electron — that’s your signature that tells you about the neutrino.”