ASTM E526-17

5.1 Refer to Guide E844 for the selection, irradiation, and quality control of neutron dosimeters.

5.2 Refer to Test Method E261 for a general discussion of the determination of fast-neutron fluence rate with threshold detectors.

5.3 Titanium has good physical strength, is easily fabricated, has excellent corrosion resistance, has a melting temperature of 1668°C, and can be obtained with satisfactory purity.

5.4 ⁴⁶Sc has a half-life of 83.787 (16)5.5 The isotopic content of natural titanium recommended for  ⁴⁶Ti is 8.25 %. (2)

5.6 The radioactive products of the neutron reactions   ⁴⁷Ti(n,p)⁴⁷Sc (τ_{5.7 Contaminant activities (for example,   ⁶⁵Zn and  ¹⁸²Ta) might interfere with the analysis of  ⁴⁶Sc. See 7.1.2 and 7.1.3 for more details on the  ¹⁸²Ta and  ⁶⁵Zn interference.}

5.8 ⁴⁶Ti and  ⁴⁶Sc have cross sections for thermal neutrons of 0.59 ± 0.18 and 8.0 ± 1.0 barns, respectively 5.9 Fig. 1 shows a plot of the Russian Reactor Dosimetry File (RRDF-2002) cross section FIG. 1 ^NatTi(n,X)⁴⁶Sc Cross Section (Normalized per Ti-46 Atom Using Natural Abundance Data)

1.1 This test method covers procedures for measuring reaction rates by the activation reactions  ⁴⁶Ti(n,p) ⁴⁶Sc + ⁴⁷Ti(n, np)⁴⁶Sc + ⁴⁷Ti(n,d)⁴⁶Sc.

1.2 The reaction is useful for measuring neutrons with energies above approximately 4.4 MeV and for irradiation times, under uniform power, up to about 250 days (for longer irradiations, or for varying power levels, see Practice E261).

1.3 With suitable techniques, fission-neutron fluence rates above 10⁹ cm^–2·s^–1 can be determined. However, in the presence of a high thermal-neutron fluence rate, ⁴⁶Sc depletion should be investigated.

1.4 Detailed procedures for 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 of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.