ASTM E263-2018 用铁的放射性测量快中子反应速率的方法 Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Iron

1.1 This test method describes procedures for measuring reaction rates by the activation reaction ⁵⁴Fe(n,p)⁵⁴Mn.

1.2 This activation reaction is useful for measuring neutrons with energies above approximately 2.2 MeV and for irradiation times up to about three years, provided that the analysis methods described in Practice E261 are followed. If dosimeters are analyzed after irradiation periods longer than three years, the information inferred about the fluence during irradiation periods more than three years before the end of the irradiation should not be relied upon without supporting data from dosimeters withdrawn earlier.

1.3 With suitable techniques, fission-neutron fluence rates above 10⁸ cm⁻²·s⁻¹ can be determined. However, in the presence of a high thermal-neutron fluence rate (for example, >2 × 10¹⁴ cm⁻²·s ⁻¹) ⁵⁴Mn depletion should be investigated.

1.4 Detailed procedures describing the use of other fast-neutron detectors are referenced in Practice E261.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address all