BS ISO 8529-1:2001 - Page 2

Reference neutron radiations. Characteristics and methods of production | Status: Superseded, Withdrawn

1 Scope This part of ISO 8529 specifies the reference neutron radiations, in the energy range from thermal up to 20 MeV, for calibrating neutron-measuring devices used for radiation protection purposes and for determining their response as a function of neutron energy. Reference radiations are given for neutron fluence rates of up to 1 × 109 m−2·s−1, corresponding, at a neutron energy of 1 MeV, to dose-equivalent rates of up to 100 mSv·h−1. This part of ISO 8529 is concerned only with the methods of producing and characterizing the neutron reference radiations. The procedures for applying these radiations for calibrations are described in ISO 8529-2 and ISO 8529-3. The reference radiations specified are the following:

• — neutrons from radionuclide sources, including neutrons from sources in a moderator;
• — neutrons produced by nuclear reactions with charged particles from accelerators;
• — neutrons from reactors.

In view of the methods of production and use of them, these reference radiations are divided, for the purposes of this part of ISO 8529, into the following two separate sections.

• — In clause 4, radionuclide neutron sources with wide spectra are specified for the calibration of neutron-measuring devices. These sources should be used by laboratories engaged in the routine calibration of neutron-measuring devices, the particular design of which has already been type tested.
• — In clause 5, accelerator-produced monoenergetic neutrons and reactor-produced neutrons with wide or quasi monoenergetic spectra are specified for determining the response of neutron-measuring devices as a function of neutron energy. Since these reference radiations are produced at specialized and well equipped laboratories, only the minimum of experimental detail is given.

For the conversion of neutron fluence into the quantities recommended for radiation protection purposes, conversion coefficients have been calculated based on the spectra presented in normative annex A and using the fluence-to-dose-equivalent conversion coefficients as a function of neutron energy as given in ICRP Publication 74 and ICRU Report 57.