Only 15 minutes of life, no fame, for lone neutrons
Once freed from its home inside the nucleus of an atom, a neutron lives on average 886.8 seconds (about 14.8 minutes), plus or minus 3.4 seconds, according to recent measurements performed at the National Institute of Standards and Technology.
This result, published in the Oct. 10 issue of Physical Review Letters, is the most precise ever achieved using beams of neutrons and is the culmination of almost 10 years of work. The new neutron lifetime value is consistent with physicists current theories about the particles and forces of nature. It also will help scientists better understand the creation of matter immediately after the birth of the universe, an important factor in determining what the universe is made of today.
Scientists have been measuring the lifetime of the neutron since the early 1950s. While slightly less precise than a measurement made in 2000 by a different research group using a different method, the in-beam technique provides a strong, independent check on the neutron lifetime and reduces the overall uncertainty in the recommended value.
As neutrons die, they disintegrate into other particles, including protons. The NIST-led group simultaneously counted both the number of neutrons and the number of protons formed as the neutrons fell apart. A beam of slow moving neutrons was passed through a vacuum system. As the neutrons decayed, protons—which have a positive charge—formed and were captured in a powerful electromagnetic trap. Periodically the trap was opened and the protons were counted as they crashed into a semiconductor detector, producing an electrical signal.
The research team included participants from NIST, Tulane University, Indiana University, University of Tennessee/Oak Ridge National Laboratory, and the European Commissions Joint Research Centre (Institute for Reference Materials and Measurements) in Belgium.
The research was funded by NIST, the U.S. Department of Energy and the National Science Foundation.
Alle Nachrichten aus der Kategorie: Physics and Astronomy
This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.
innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.
Argonne targets lithium-rich materials as key to more sustainable cost-effective batteries
Next-generation batteries using lithium-rich materials could be more sustainable and cost-effective, according to a team of researchers with the U.S. Department of Energy’s (DOE) Argonne National Laboratory. The pivotal discovery,…
Why disordered light-harvesting systems produce ordered outcomes
Scientists typically prefer to work with ordered systems. However, a diverse team of physicists and biophysicists from the University of Groningen found that individual light-harvesting nanotubes with disordered molecular structures…
RadarGlass – from vehicle headlight to radar transceiver
As a result of modern Advanced Driver Assistance Systems, the use of radar technology has become indispensable for the automotive sector. With the installation of a large and growing number…