ISO 80000-10:2019

Overview - ISO 80000-10:2019 (Quantities and units - Atomic and nuclear physics)

ISO 80000-10:2019 defines names, symbols, definitions and units for quantities used in atomic and nuclear physics. This second edition (2019) updates and simplifies the tables of quantities and aligns many definitions with ICRU recommendations. Where appropriate, conversion factors and guidance on the use of CODATA recommended values for physical constants are provided. The standard is part of the ISO/IEC 80000 series on quantities and units and is intended to ensure consistent terminology and unit usage in research, engineering and metrology.

Key topics and technical content

The standard systematically lists and defines atomic and nuclear physics quantities, including (but not limited to):

• Atomic and nuclear identifiers: atomic number (Z), neutron number (N), nucleon/mass number (A).
• Mass and energy: rest mass, rest energy, atomic mass, nuclidic mass and the unified atomic mass constant.
• Charge and constants: elementary charge, charge (ionization) number, and reference to CODATA values for constants.
• Atomic units and spectroscopic constants: Bohr radius, Rydberg constant, Hartree energy, and their units (eV, J, Å, Da/u).
• Magnetic properties: magnetic dipole, Bohr magneton, nuclear magneton, gyromagnetic (magnetogyric) ratios.
• Quantum quantities: spin, total angular momentum, principal/orbital quantum numbers and related quantum-state notation.
• Stochastic vs non‑stochastic quantities: treatment of statistical (stochastic) quantities in radiation metrology (expected/mean values, differential quotients).

The document provides precise definitions, units (SI and commonly used units like eV and Da), and remarks on applicability and measurement context. It contains no normative references and draws on CODATA for numerical constants (see CODATA/NIST).

Practical applications and users

ISO 80000-10 is valuable for anyone who needs authoritative, standardized nomenclature in atomic and nuclear contexts:

• Researchers and academics preparing publications, textbooks and datasets.
• Metrologists and standards bodies ensuring traceability and consistent units in measurements.
• Instrument and software developers (spectroscopy, nuclear instrumentation, simulation tools) for consistent parameter naming and unit handling.
• Medical physics, radiation protection and nuclear engineering professionals who require unambiguous definitions for dose-related and particle-related quantities.
• Data curators and database providers who exchange or annotate atomic/nuclear data.

Using ISO 80000-10 promotes interoperability, reduces ambiguity in scientific communication, and supports accurate unit conversion and reporting.

Related standards

• ISO/IEC 80000 series (quantities and units)
• IEC 80000 parts referenced for electromagnetic quantities
• ICRU reports and CODATA recommended values for fundamental constants (CODATA/NIST)