The worlds best clock, NIST-F1, has been improved over the past few years and now measures time and frequency more than twice as accurately as it did in 1999 when first used as a national standard, physicists at the National Institute of Standards and Technology (NIST) report.
The improved version of NIST-F1 would neither gain nor lose one second in 60 million years, according to a paper published online Sept. 13 by the journal Metrologia.* NIST-F1 uses a fountain-like movement of cesium atoms to determine the length of the second. The clock measures the natural oscillations of the atoms to produce more than 9 billion "ticks" per second. These results then contribute to the international group of atomic clocks that define the official world time. NIST-F1 has been formally evaluated 15 times since 1999; in its record performance, it measured the second with an uncertainty of 0.53 × 10-15
The improved accuracy is due largely to three factors, according to Tom Parker, leader of the NIST atomic standards research group. First, better lasers, software and other components have made the entire NIST-F1 system much more reliable and able to operate for longer periods of time. Second, the atoms in the cesium vapor are now spread out over a much larger volume of space, reducing the frequency shifts caused by interactions among the atoms. (The formerly round cloud of atoms is now shaped like a short cigar.) Third, scientists are now better able to control magnetic fields within the clock and quantify the corrections needed to compensate for their effects on the atoms.
Laura Ost | EurekAlert!
Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen
New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy