Related Experiment Video
Updated: Jun 17, 2026

10:42
Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
Algorithms for international atomic time.
Gianna Panfilo1, E Felicitas Arias
1International Bureau for Weights and Measures (BIPM), Sevres, France. gpanfilo@bipm.org
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
|December 31, 2009
Summary
This article details the creation and evolution of atomic time scales, focusing on International Atomic Time (TAI). It explains TAI
Area of Science:
- Metrology
- Physics
- Timekeeping
Background:
- Atomic time scales are fundamental to modern science and technology.
- The need for precise timekeeping has driven significant advancements in metrology.
Purpose of the Study:
- To review the historical development and technical evolution of atomic time scales.
- To elucidate the calculation methods and characteristics of International Atomic Time (TAI).
- To describe the dissemination of TAI with ultimate precision.
Main Methods:
- Review of historical data and technical literature on atomic time scale creation.
- Analysis of the algorithms and methodologies employed in calculating International Atomic Time (TAI).
- Examination of the systems and protocols for disseminating TAI.
Main Results:
- Detailed account of the progression of atomic time scale technology.
- Comprehensive description of the calculation methods and defining characteristics of TAI.
- Explanation of the high-precision dissemination techniques for TAI.
Conclusions:
- International Atomic Time (TAI) represents a pinnacle in the evolution of precise timekeeping.
- Understanding TAI's creation, calculation, and dissemination is crucial for scientific and technological applications.
More Related Videos
Related Concept Videos
International System of Units
The International System of Units, known as the SI system, is a universally accepted measurement system recognized and used worldwide. The SI system is based on a set of three base units considered absolute, and their values do not change with location. These base units are meters, kilograms, and seconds.
Prefixes are used to define both larger and smaller quantities in the SI system. For example, milli, micro, and nano define smaller quantities, while kilo, mega, and giga are used to define...
Prefixes are used to define both larger and smaller quantities in the SI system. For example, milli, micro, and nano define smaller quantities, while kilo, mega, and giga are used to define...
Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
Measurement: Standard Units
Every measurement provides three kinds of information: the size or magnitude of the measurement (a number), a standard of comparison for the measurement (a unit), and an indication of the uncertainty of the measurement. While the number and unit are explicitly represented when a quantity is written, the uncertainty is an aspect of the errors in the measurement results.
Atomic Nuclei: Types of Nuclear Relaxation
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
Atomic Absorption Spectroscopy: Interference
Interference leads to systematic error in atomic absorption (AA) measurements by enhancing or diminishing the analytical signal or the background. These interferences can be grouped into three main categories: spectral interference, chemical interference, and physical interference.
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
Atomic Weight
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams. Scientists arbitrarily define this amount of mass as one atomic mass unit (amu) or one Dalton. Electrons are much smaller in mass than protons, weighing only 9.11 × 10-28 grams, or about 1/1800 of an atomic mass unit. As a result, they do not contribute much to an element's overall atomic mass. This means that, when considering atomic mass, it is customary to ignore the mass of any electrons and calculate the...

