Science: A small neutrino detector has been found to actually work!

Science News reports:

A tiny neutrino detector scored big at a nuclear reactor

Conventional detectors of the subatomic particles require metric tons of material. But the new detector has a mass of less than 3 kilograms. Think chihuahua. And it successfully detected antineutrinos, the antimatter counterparts of neutrinos, streaming from a nuclear power plant in Leibstadt, Switzerland, researchers report in a paper submitted January 9 to arXiv.org.

“This is actually huge,” says neutrino physicist Kate Scholberg of Duke University, who was not involved with the research. “People have been trying to do this for many decades and now have finally succeeded.”

Similar scaled-down neutrino detectors have glimpsed neutrinos and antineutrinos created by laboratory sources of the particles. Nuclear reactors spit out relatively low-energy antineutrinos. By measuring those low-energy particles, such detectors could help test physics theories or reveal the inner workings of atomic nuclei. Some scientists have proposed that the compact devices could used to monitor nuclear reactors for activity that signals development of nuclear weapons.

Neutrinos are dastardly difficult to spot. For the most part, they interact with matter so rarely that detectors need to be enormous to provide more opportunities for neutrinos to interact within.

But one type of interaction is more common, in which a neutrino or antineutrino bounces off an atomic nucleus rather than a proton or neutron. Detectors of neutrino-nucleus interactions can be built quite small — with a catch. They must be extremely sensitive. Observing the nucleus recoiling is like sensing the motion of a bowling ball hit by a ping-pong ball. The effect was first observed in 2017, using a laboratory source of the particles.

In the new study, a detector made of germanium crystals snagged about 400 antineutrinos from the Leibstadt reactor over 119 days. The number agrees with predictions from the established theory of particle physics, the standard model.

The chihuahua!

The neutrino detector (copper) is surrounded with layers of lead (black) and polyethylene (red and white) to block other types of subatomic particles, and (blue) layers (of stuff) detect particles that might otherwise be confused with antineutrinos

In a neutrino-nucleus interaction, the complexity of the nucleus, with its constituent protons and neutrons, is washed out. It’s truly like knocking into a bowling ball. And the lower the energy of the particles hitting that nucleus, the more like a bowling ball it is. With reactor antineutrinos, “it’s just such a gentle bump that it’s very clean,” Scholberg says. “Any sort of weird mushy stuff going on in the nucleus doesn’t matter.”

The lack of mushiness makes the measurements more sensitive to potential new effects, such as undiscovered types of particles or unexpected magnetism in neutrinos. “This opens up a new channel in neutrino physics,” says physicist Christian Buck of the Max Planck Institute for Nuclear Physics in Heidelberg, a coauthor of the study. “There might be new physics in that channel that we do not know about now.” Other teams of scientists are already using the data to check for such effects, as reported in two papers submitted to arXiv.org on January 17 and January 21.

See, atomic nuclei aren't mushy with neutrinos. They're bowling balls! Now some good stuff is gonna get done. Now we can detect rogue nations or groups building atomic bombs!

By Germaine: Keeping eyes 👀 on science, and germanium and Germaineum crystals 

A 1 kg (2.20 lb) ingot of 99.9999% pure germanium 

costs around $2,500

A 1 kg (2.20 lb) ingot of 99.9999% pure Germaneium 

costs around $2.5 billion