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 1675??C, and can be obtained with satisfactory purity.
5.4 46Sc has a half-life of 83.79 days.3 The 8201;46Sc decay4 emits a 0.8893 MeV gamma 99.9848201;% of the time and a second gamma with an energy of 1.1205 MeV 99.9878201;% of the time.
5.5 The isotopic content of natural titanium recommended for 8201;46Ti is 8.258201;%.3
5.6 The radioactive products of the neutron reactions 8201; 47Ti(n,p)47Sc (??1/2 = 3.3492 d) and 8201; 48Ti(n,p)48Sc (??1/2 = 43.67 h), might interfere with the analysis of 8201;46Sc.
5.7 Contaminant activities (for example, 8201; 65Zn and 8201;182Ta) might interfere with the analysis of 8201;46Sc. See Sections 7.1.2 and 7.1.3 for more details on the 8201;182Ta and 8201;65Zn interference.
5.8 46Ti and 8201;46Sc have cross sections for thermal neutrons of 0.59 and 8 barns, respectively5; therefore, when an irradiation exceeds a thermal-neutron fluence greater than about 2 ?? 1021 cm???2, provisions should be made to either use a thermal-neutron shield to prevent burn-up of 8201; 46Sc or measure the thermal-neutron fluence rate and calculate the burn-up.
5.9 Fig. 1 shows a plot of cross section versus neutron energy for the fast-neutron reactions of titanium which produce 8201; 46Sc [that is, NatTi(n,X)46Sc]. Included in the plot is the 8201;46Ti(n,p) reaction6 and the 8201; 47Ti(n,np) contribution to the 8201;46Sc production,7 normalized (at 14.7 MeV)8 per 8201; 46Ti atom. This figure is for illustrative purposes only to indicate......