Neutrons have many uses. Their ability to induce nuclear fission makes them fundamental to nuclear power. Their penetrating nature makes them useful probes into the composition and structure of materials. In addition to their industrial uses they have medical applications, such as isotope production. In all cases, it is important to know how many neutrons there are, and what risk they pose to anyone present.
A number of radionuclide sources (with broad energy spectra) are available at NPL for measurement services, as are monoenergetic neutrons derived from the NMG's 3.5 MV Van de Graaff accelerator.
Another key area of the NMG's capabilities is field measurements using active and passive systems to measure neutron fluence rates and energy spectra. Also available are several novel instruments such as those for measuring cosmic ray doses to air crew.
Research is undertaken within the Group to develop the range of standards and to address some of the deficiencies of neutron measuring devices.