This part of ISO 21909 provides performance and test requirements for determining the acceptability of neutron dosimetry systems to be used for the measurement of personal dose equivalent, Hp(10), for neutrons ranging in energy from thermal to 20 MeV1). No distinction between the different techniques available in the market place is made in the description of the tests. Only generic distinctions, as disposable or reusable dosemeters for instance, are considered. This part of ISO 21909 gives information for extremity dosimetry, based on recommendations given by ICRU Report 66 in Annex A.