ASTM E 263 : 2013

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

1.2This activation reaction is useful for measuring neutrons with energies above approximately 2.2 MeV and for irradiation times up to about 3 years (for longer irradiations, see Practice E261).

1.3With 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.

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

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

1.6This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.