Miniature Neutrino Detector Promises to Test the Laws of Physics
'They finally did it,' says Kate Scholberg, a physicist at Duke University in Durham, North Carolina. 'And they have very beautiful result.' The experiment, called CONUS+, is described on 30 July in Nature.
Challenging quarry
On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Neutrinos are elementary particles that have no electrical charge and generally don't interact with other matter, making them extraordinarily difficult to detect. Most neutrino experiments catch these elusive particles by observing flashes of light that are generated when a neutrino collides with an electron, proton or neutron. These collisions occur extremely infrequently, so such detectors typically have masses of tonnes or thousands of tonnes to provide enough target material to gather neutrinos in relevant numbers.
Scholberg and her collaborators first demonstrated the mini-detector technique in 2017, using it to catch neutrinos produced by an accelerator at Oak Ridge National Laboratory in Tennessee. The Oak Ridge particles have slightly higher energies than those made in reactors. As a result, detecting reactor neutrinos was even more challenging, she says. But lower-energy neutrinos also allow for a more precise test of the standard model of physics.
Scholberg's COHERENT detector was the first to exploit a phenomenon called coherent scattering, in which a neutrino 'scatters' off an entire atomic nucleus rather than the atom's constituent particles.
Coherent scattering uses the fact that particles of matter can act as waves — and the lower the particles' energy, the longer their wavelength, says Christian Buck, a leader of the CONUS collaboration. If the wavelength of a neutrino is similar to the nucleus's diameter, 'then the neutrino sees the nucleus as one thing. It doesn't see the internal structure', says Buck, who is a physicist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. The neutrino doesn't interact with any subatomic particles, but does cause the nucleus to recoil — depositing a tiny amount of energy into the detector.
Catching sight of a nucleus
Coherent scattering occurs more than 100 times as frequently as the interactions used in other detectors, where the neutrino 'sees' a nucleus as a collection of smaller particles with empty space in between. This higher efficiency means that detectors can be smaller and still spot a similar number of particles in the same time frame. 'Now you can afford to build detectors on the kilogram scale,' Buck says.
The downside is that the neutrinos deposit much less energy at the nucleus. The recoil induced on a nucleus by a neutrino is comparable to that produced on a ship by a ping-pong ball, Buck says — and has until recent years has been extremely challenging to measure.
The CONUS detector is made of four modules of pure germanium, each weighing 1 kilogram. It operated at a nuclear reactor in Germany from 2018 until that reactor was shut down in 2022. The team then moved the detector, upgraded to CONUS+, to the Leibstadt nuclear power plant in Switzerland. From the new location, the team now reports having seen around 395 collision events in 119 days of operation — consistent with the predictions of the standard model of particle physics.
After COHERENT's landmark 2017 result, which was obtained with detectors made of caesium iodide, Scholberg's team repeated the feat with detectors made of argon and of germanium. Separately, last year, two experiments originally designed to hunt for dark matter reported seeing hints of low-energy coherent scattering of neutrinos produced by the Sun. Scholberg says that the standard model makes very clean predictions of the rate of coherent scattering and how it changes with different types of atomic nucleus, making it crucial to compare results from as many detecting materials as possible. And if the technique's sensitivity improves further, coherent scattering could help to push forward the state of the art of solar science.
Researchers say that coherent scattering will probably not completely replace any existing technologies for detecting neutrinos. But it can spot all three known types of neutrino (and their corresponding antiparticles) down to low energies, whereas some other techniques can capture only one type. This ability means it could complement massive detectors that aim to pick up neutrinos at higher energies, such as the Hyper-Kamiokande observatory now under construction in Japan.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
15 hours ago
- Yahoo
Compact detector unlocks reactor's neutrino mystery with first-ever detection
Scientists at the Max Planck Institute for Nuclear Physics (MPIK) have detected antineutrinos from a nuclear reactor using a 3 kg (6.6 lbs) detector. The results were achieved using the CONUS+ experiment and provide an observation of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) from a reactor source at full coherence. 'The CEvNS measurement provides unique insights into fundamental physical processes within the Standard Model of particle physics, the current theory describing the structure of our universe,' said the researchers in a press release. Neutrinos do not scatter off The experiment is situated 20.7 meters from the core of the Leibstadt nuclear power plant in Switzerland. It uses three 1 kg (2.2 lbs) germanium semiconductor detectors to identify CEvNS, a process where a low-energy neutrino interacts with an entire atomic nucleus. 'In this process, neutrinos do not scatter off the individual components of the atomic nuclei in the detector, but rather coherently with the entire nucleus. This significantly increases the probability of a very small but observable nuclear recoil,' explained the press release. The process can be compared to a ping-pong ball hitting a car; the recoil of the car, though small, is the observable effect. In this case, antineutrinos from the reactor scattered off germanium nuclei in the detectors. Over a measurement period of 119 days between 2023 and 2024, the team recorded an excess of 395±106 neutrino signals after subtracting background and interfering signals. The position of the detector receives a flux of more than 1013 (ten trillion) neutrinos per square centimeter per second from the reactor. "This value is in very good agreement with theoretical calculations, within the measurement uncertainty," remarked the press release. "We have thus successfully confirmed the sensitivity of the CONUS+ experiment and its ability to detect antineutrino scattering from atomic nuclei," added Dr. Christian Buck, an author of the study. Neutrino detection requires large experiments Neutrinos are elementary particles that interact weakly with matter, and their detection has typically required very large experiments. The CEvNS effect was theorized in 1974 and first observed by the COHERENT experiment at a particle accelerator in 2017. The CONUS+ result is the first observation of the effect from a reactor at these low energies. The CEvNS technique may have future applications. Dr. Buck noted the potential to develop small, mobile neutrino detectors to monitor reactor heat output or isotope concentration. The measurement also provides data for testing the Standard Model of particle physics. According to the authors, the CONUS+ measurements have a reduced dependence on nuclear physics aspects compared to other experiments, improving the sensitivity to physics beyond the Standard Model. "The techniques and methods used in CONUS+ have excellent potential for fundamental new discoveries," concluded Professor Manfred Lindner, the project's initiator. "The groundbreaking CONUS+ results could therefore mark the starting point for a new field in neutrino research." The experiment was equipped with improved and larger detectors in autumn 2024, with the aim of increasing measurement accuracy. Solve the daily Crossword
Yahoo
16 hours ago
- Yahoo
Miniature Neutrino Detector Catches Elusive Particles at Nuclear Reactor
A relatively small detector caught neutrinos from a nuclear reactor using a technique known as coherent scattering Physicists have caught neutrinos from a nuclear reactor using a device weighing just a few kilograms, orders of magnitude less massive than standard neutrino detectors. The technique opens new ways to stress-test the known laws of physics and to detect the copious neutrinos produced in the hearts of collapsing stars. 'They finally did it,' says Kate Scholberg, a physicist at Duke University in Durham, North Carolina. 'And they have very beautiful result.' The experiment, called CONUS+, is described on 30 July in Nature. Challenging quarry Neutrinos are elementary particles that have no electrical charge and generally don't interact with other matter, making them extraordinarily difficult to detect. Most neutrino experiments catch these elusive particles by observing flashes of light that are generated when a neutrino collides with an electron, proton or neutron. These collisions occur extremely infrequently, so such detectors typically have masses of tonnes or thousands of tonnes to provide enough target material to gather neutrinos in relevant numbers. [Sign up for Today in Science, a free daily newsletter] Scholberg and her collaborators first demonstrated the mini-detector technique in 2017, using it to catch neutrinos produced by an accelerator at Oak Ridge National Laboratory in Tennessee. The Oak Ridge particles have slightly higher energies than those made in reactors. As a result, detecting reactor neutrinos was even more challenging, she says. But lower-energy neutrinos also allow for a more precise test of the standard model of physics. Scholberg's COHERENT detector was the first to exploit a phenomenon called coherent scattering, in which a neutrino 'scatters' off an entire atomic nucleus rather than the atom's constituent particles. Coherent scattering uses the fact that particles of matter can act as waves — and the lower the particles' energy, the longer their wavelength, says Christian Buck, a leader of the CONUS collaboration. If the wavelength of a neutrino is similar to the nucleus's diameter, 'then the neutrino sees the nucleus as one thing. It doesn't see the internal structure', says Buck, who is a physicist at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. The neutrino doesn't interact with any subatomic particles, but does cause the nucleus to recoil — depositing a tiny amount of energy into the detector. Catching sight of a nucleus Coherent scattering occurs more than 100 times as frequently as the interactions used in other detectors, where the neutrino 'sees' a nucleus as a collection of smaller particles with empty space in between. This higher efficiency means that detectors can be smaller and still spot a similar number of particles in the same time frame. 'Now you can afford to build detectors on the kilogram scale,' Buck says. The downside is that the neutrinos deposit much less energy at the nucleus. The recoil induced on a nucleus by a neutrino is comparable to that produced on a ship by a ping-pong ball, Buck says — and has until recent years has been extremely challenging to measure. The CONUS detector is made of four modules of pure germanium, each weighing 1 kilogram. It operated at a nuclear reactor in Germany from 2018 until that reactor was shut down in 2022. The team then moved the detector, upgraded to CONUS+, to the Leibstadt nuclear power plant in Switzerland. From the new location, the team now reports having seen around 395 collision events in 119 days of operation — consistent with the predictions of the standard model of particle physics. After COHERENT's landmark 2017 result, which was obtained with detectors made of caesium iodide, Scholberg's team repeated the feat with detectors made of argon and of germanium. Separately, last year, two experiments originally designed to hunt for dark matter reported seeing hints of low-energy coherent scattering of neutrinos produced by the Sun. Scholberg says that the standard model makes very clean predictions of the rate of coherent scattering and how it changes with different types of atomic nucleus, making it crucial to compare results from as many detecting materials as possible. And if the technique's sensitivity improves further, coherent scattering could help to push forward the state of the art of solar science. Researchers say that coherent scattering will probably not completely replace any existing technologies for detecting neutrinos. But it can spot all three known types of neutrino (and their corresponding antiparticles) down to low energies, whereas some other techniques can capture only one type. This ability means it could complement massive detectors that aim to pick up neutrinos at higher energies, such as the Hyper-Kamiokande observatory now under construction in Japan. This article is reproduced with permission and was first published on July 30 2025. Solve the daily Crossword
Yahoo
a day ago
- Yahoo
Could a single shot at birth shield kids from HIV for years?
There's potentially exciting news from a trial conducted in monkeys: A single shot of gene therapy given to newborn monkeys appears to shield them from HIV, the virus that causes AIDS, for at least three years. Of course, studies conducted in animals don't always pan out in humans. But scientists say that if it does, it could save the lives of babies and children still imperiled by HIV. The study authors estimate that more than 100,000 children worldwide (largely in subSaharan Africa) are believed to contract HIV soon after birth, primarily via breastfeeding with an HIV+ mother. "Nearly 300 children are infected with HIV each day," said lead author Dr. Amir Ardeshir, associate professor of microbiology and immunology at the Tulane National Primate Research Center in New Orleans. "This approach could help protect newborns in high-risk areas during the most vulnerable period of their lives." His team published its findings July 30 in Nature. It noted that the new work hinges on the notion that in the first few weeks of a primate's life -- humans are primates, too -- the body's immune system is naturally more tolerant of "invaders," including gene therapies. The research focused on a tried-and-true form of HIV-fighting gene therapy. It works by programming cells to continuously produce HIV-fighting antibodies. The gene therapy was piggybacked onto a harmless adeno-associated virus (AAV) to help deliver it to the muscle cells of newborn rhesus macaques. Muscle cells were chosen because they are particularly long-lived, Ardeshir's team explained. The gene therapy instructs these cells to produce broadly neutralizing antibodies, or bNAbs, which are capable of neutralizing multiple strains of HIV. It's not the first time bNAbs have been used in gene therapy to fight HIV. However, in prior trials repeat injections were required to keep the immune system vigilant. In the new trial, "we turn these muscle cells -- which are long-lived -- into micro factories that just keep producing these antibodies," Ardeshir explained. When such an approach is used in older monkeys, however, the animals' robust immune systems turn against the therapy, shutting it down. That didn't happen when Ardeshir's team introduced it during a macaque's first few weeks of life. All of the monkeys who got a single shot of bNAbs therapy soon after birth were shielded from infection with HIV for at least three years, with no need for a booster. Tulane researchers said that's roughly the equivalent of a treatment that could ward off HIV in humans deep into adolescence. If the gene therapy was delivered even a bit later -- 8 to 12 weeks after birth -- the young monkey's more developed immune system swung into action to fight it, eroding its effectiveness. Giving the shot soon after birth seemed key, Ardeshir said. "This is a one-and-done treatment that fits the critical time when these mothers with HIV in resource-limited areas are most likely to see a doctor," he noted in a Tulane news release. "As long as the treatment is delivered close to birth, the baby's immune system will accept it and believe it's part of itself." Will it work in human babies? That's not entirely clear, since it's possible infants might be less amenable than monkeys to therapies that are delivered via AAV, the team said. The monkey trial also used only one strain of simian-human immunodeficiency virus, which is similar in some ways to HIV but may not reflect the variety of circulating strains of HIV strains. Still, the research team is hopeful. Giving families a one-shot preventive tool to protect their children would be especially useful in areas where access to repeat medical treatments can be tough, the researchers said. "Nothing like this was possible to achieve even 10 years ago," Ardeshir said. "This was a huge result, and now we have all the ingredients to take on HIV." More information Find out more about HIV and AIDS at the U.S. Centers for Disease Control and Prevention (CDC). SOURCE: Tulane University, news release, July 30, 2025 Copyright © 2025 HealthDay. All rights reserved.
