1.1 This test method describes procedures measuring reaction rates by the activation reaction 27 Al(n,[alpha]) 24 Na.

1.2 This activation reaction is useful for measuring neutrons with energies above approximately 6.5 MeV and for irradiation times up to about 2 days (for longer irradiations, see Test Method E261).

1.3 With suitable techniques, fission-neutron fluence rates above 10 [dot]cm -2 [dot]s -1 can be determined.

1.4 Detailed procedures for other fast neutron detectors are referenced in Test Method E261.

1.5 This standard does not purport to address all of the safety problems, 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.