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Nuclear checks, the neutrino way
This week
Jacob Aron
IT ISN’T yours, but you’d like to peer inside without annoying the owner. Such is the challenge of international nuclear inspections. An experimental kind of particle detector could come in handy, giving us a new way of finding out whether a reactor is producing material for weapons. Earlier this year, Iran agreed a deal with major world powers to limit its nuclear activities, promising it will allow monitors from the International Atomic Energy Agency (IAEA) to inspect its plants and ensure they are being used for peaceful purposes. The deal is built on fragile trust – Iran doesn’t want to reveal any more of its nuclear secrets than it has to. A device to monitor reactors remotely, with no need for foreign inspectors to visit, would help. As it turns out, we know how to build specialised detectors for particles called neutrinos. Produced by nuclear reactions, they barely interact with ordinary matter, so stream away from reactors and can be picked up far away with a suitable instrument.
One-two punch may have killed off dinosaurs IT WAS one thing after another for the dinosaurs. The famous asteroid that hastened their demise touched down in the middle of a period of climate change caused by intense volcanism. The resulting seismic shock may have then triggered even more eruptions, suggesting a one-two punch saw off Tyrannosaurus and co. This interpretation could help bring 10 | NewScientist | 10 October 2015
For the past year, researchers in France have used one such detector, dubbed Nucifer, to monitor a small reactor next door. Nucifer is full of a liquid scintillator that flashes on the rare occasions when a neutrino interacts with it. The rate at which this happens reveals the activity level inside the reactor. Despite the presence of other energetic particles, the team was able to create shielding for Nucifer and get useful readings. Over the course of 145 days, the team could detect when the reactor was running, and track the amount of plutonium-239 inside (arxiv.org/ abs/1509.05610). This isotope is especially useful for producing nuclear weapons, so any sudden change in its level suggests armaments may be the reactor’s actual purpose. Researchers have already built detectors of this type in Russia and the US, but they were one-off creations and required frequent maintenance, which wouldn’t be practical in the context of monitoring. “With Nucifer, we wanted to improve the performance and use off-the-shelf parts,” says team member David
together two schools of thought on what caused one of the largest mass extinctions in our planet’s history, 66 million years ago. The dominant theory is that the asteroid impact was chiefly responsible for wiping out threequarters of the species then alive. Another line of thought is that climate change triggered by vast volcanic eruptions led to the downfall of the dinosaurs. A region called the Deccan traps in modern-day India oozed more than a million cubic kilometres of lava over about 800,000 years, releasing sulphur
Grosjean/CEA
Nuclear checks, the neutrino way
–The evidence is just streaming out–
Lhuillier of the Saclay Nuclear Research Centre near Paris. The neutrino output of a fullscale reactor would be big enough that the detector could be installed at a discreet distance, with inspectors logging in remotely. The team is now trying to find one for further tests. “We could put the detector in place, close the door and leave it like that for one year, in conditions very close to what the IAEA inspectors would like to
see,” says Lhuillier. But it will probably be at least 15 years before it is ready for real-world use. The IAEA told New Scientist that they have no imminent plans to deploy the technology. But Patrick Huber of Virginia Tech in Blacksburg, who works on similar detectors, says Nucifer is a great step forward. “We’re not quite there yet, but it goes a very long way from where we were 10 years ago,” he says. n
dioxide and carbon dioxide, and warming the atmosphere. Now there is evidence that the worst of these lava flows happened after the impact. Paul Renne of Berkeley Geochronology Center in California and his team reached this conclusion by using argon isotopes to date Deccan rocks (Science, doi. org/74q). “Suddenly the lava flows erupting in the Deccan traps are much
thicker and much more widely distributed,” Renne says. “Thousands of kilometres are affected.” The finding backs up a theory published earlier this year by Mark Richards, a colleague of Renne’s at Berkeley. The shock waves from the Chicxulub asteroid – equivalent to those of a magnitude-11 earthquake – may have agitated a plume of mantle material fuelling the Deccan traps from below, he says. Continued eruptions for another half a million years may then have made it harder for ecosystems to bounce back. Joshua Sokol n
“Suddenly the lava flows erupting in the Deccan traps are much thicker and more widely distributed”
Jacob Aron
IT ISN’T yours, but you’d like to peer inside without annoying the owner. Such is the challenge of international nuclear inspections. An experimental kind of particle detector could come in handy, giving us a new way of finding out whether a reactor is producing material for weapons. Earlier this year, Iran agreed a deal with major world powers to limit its nuclear activities, promising it will allow monitors from the International Atomic Energy Agency (IAEA) to inspect its plants and ensure they are being used for peaceful purposes. The deal is built on fragile trust – Iran doesn’t want to reveal any more of its nuclear secrets than it has to. A device to monitor reactors remotely, with no need for foreign inspectors to visit, would help. As it turns out, we know how to build specialised detectors for particles called neutrinos. Produced by nuclear reactions, they barely interact with ordinary matter, so stream away from reactors and can be picked up far away with a suitable instrument.
One-two punch may have killed off dinosaurs IT WAS one thing after another for the dinosaurs. The famous asteroid that hastened their demise touched down in the middle of a period of climate change caused by intense volcanism. The resulting seismic shock may have then triggered even more eruptions, suggesting a one-two punch saw off Tyrannosaurus and co. This interpretation could help bring 10 | NewScientist | 10 October 2015
For the past year, researchers in France have used one such detector, dubbed Nucifer, to monitor a small reactor next door. Nucifer is full of a liquid scintillator that flashes on the rare occasions when a neutrino interacts with it. The rate at which this happens reveals the activity level inside the reactor. Despite the presence of other energetic particles, the team was able to create shielding for Nucifer and get useful readings. Over the course of 145 days, the team could detect when the reactor was running, and track the amount of plutonium-239 inside (arxiv.org/ abs/1509.05610). This isotope is especially useful for producing nuclear weapons, so any sudden change in its level suggests armaments may be the reactor’s actual purpose. Researchers have already built detectors of this type in Russia and the US, but they were one-off creations and required frequent maintenance, which wouldn’t be practical in the context of monitoring. “With Nucifer, we wanted to improve the performance and use off-the-shelf parts,” says team member David
together two schools of thought on what caused one of the largest mass extinctions in our planet’s history, 66 million years ago. The dominant theory is that the asteroid impact was chiefly responsible for wiping out threequarters of the species then alive. Another line of thought is that climate change triggered by vast volcanic eruptions led to the downfall of the dinosaurs. A region called the Deccan traps in modern-day India oozed more than a million cubic kilometres of lava over about 800,000 years, releasing sulphur
Grosjean/CEA
Nuclear checks, the neutrino way
–The evidence is just streaming out–
Lhuillier of the Saclay Nuclear Research Centre near Paris. The neutrino output of a fullscale reactor would be big enough that the detector could be installed at a discreet distance, with inspectors logging in remotely. The team is now trying to find one for further tests. “We could put the detector in place, close the door and leave it like that for one year, in conditions very close to what the IAEA inspectors would like to
see,” says Lhuillier. But it will probably be at least 15 years before it is ready for real-world use. The IAEA told New Scientist that they have no imminent plans to deploy the technology. But Patrick Huber of Virginia Tech in Blacksburg, who works on similar detectors, says Nucifer is a great step forward. “We’re not quite there yet, but it goes a very long way from where we were 10 years ago,” he says. n
dioxide and carbon dioxide, and warming the atmosphere. Now there is evidence that the worst of these lava flows happened after the impact. Paul Renne of Berkeley Geochronology Center in California and his team reached this conclusion by using argon isotopes to date Deccan rocks (Science, doi. org/74q). “Suddenly the lava flows erupting in the Deccan traps are much
thicker and much more widely distributed,” Renne says. “Thousands of kilometres are affected.” The finding backs up a theory published earlier this year by Mark Richards, a colleague of Renne’s at Berkeley. The shock waves from the Chicxulub asteroid – equivalent to those of a magnitude-11 earthquake – may have agitated a plume of mantle material fuelling the Deccan traps from below, he says. Continued eruptions for another half a million years may then have made it harder for ecosystems to bounce back. Joshua Sokol n
“Suddenly the lava flows erupting in the Deccan traps are much thicker and more widely distributed”