Tabletop Detector That Can ‘See’ Individual Electrons

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Scientists at the Massachusetts Institute of Technology (MIT) have built a new tabletop detector that can ‘see’ individual electrons. It’s a major step toward a more challenging goal of measuring the mass of neutrinos. Scientists spent more than five years developing the detector. It is small enough to fit on top of a table, and can identify single electrons in the radioactive gas.

Tabletop detector can measure an electron’s energy

Findings of the study were published in the journal Physical Review Letters. When a radioactive gas decays and emits electrons, the tabletop detector uses a magnet to capture them in a magnetic bottle. Then a radio antenna picks up signals given off by the electrons, which are used to map the precise activity of electrons over milliseconds.

Joe Formaggio, an associate professor of physics at MIT, said they could “literally image the frequency of the electron.” Measuring the frequency of radio signals allowed researchers to measure an electron’s energy. They got precise measurements using krypton gas and they are going to try tritium gas next.

How the tabletop detector works

Most of the electrons observed by researchers behaved in a characteristic pattern. As the krypton gas decays, it gives off electrons that vibrate at a baseline frequency before tapering off. The frequency rises again when an electron bumps into a radioactive gas atom. As a result, its energy jumps in a step-like pattern.

The decay of a radioactive atom like tritium turns it into an isotope of helium. An electron and a neutrino are released in the process. The energy of all the particles released is equal to the original energy of parent neutron. So, if researchers can measure the energy of the electron, they will be able to indirectly measure the energy and mass of the neutrino.

Neutrinos are among the most mysterious particles in the universe. Every second, billions of neutrinos pass through every cell in our body. But they are difficult to identify because they don’t interact with ordinary matter.

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