1.1 本试验方法包括通过活化反应测量反应速率的程序 纳特 Ti（n，X） 46 Sc.“X”表示与残余物产生相关的轻颗粒的任何组合 46 Sc产品。在裂变反应堆应用的适用中子能量范围内，该反应是三种不同反应通道的适当归一化组合: 46 Ti（n，p） 46 Sc； 47 Ti（n，np） 46 Sc；和 47 钛（n，d） 46 Sc。 注1: 这个 47 Ti（n，np） 46 Sc反应，ENDF-6格式文件/反应标识符MF=3，MT=28，与 47 钛（n，d） 46 Sc反应，ENDF- 6格式文件/反应标识符MF=3/MT=104，即使它导致相同的残余产物 ( 1. ) . 2. IRDFF-II库中的组合反应具有文件/反应标识符MF=10/MT=5。 注2: 组合的横截面 47 Ti（n，np:d）反应相对较小，能量小于12 MeV，并且在裂变反应堆光谱中，残余 46 由于 46 Ti（n，p）反应。 1.2 该反应可用于测量能量高于约4.4MeV的中子，以及在均匀功率下的辐照时间，最长可达约250天（对于较长的辐照，或对于不同的功率水平，请参见实践 E261 ). 1.3 采用合适的技术，裂变中子注量率高于10 9 厘米 –2 ·s –1 可以确定。然而在存在高热中子注量率的情况下， 46 应调查Sc损耗。 1.4 实践中参考了其他快中子探测器的详细程序 E261 . 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ===意义和用途====== 5.1 参考指南 E844 用于中子剂量计的选择、辐照和质量控制。 5.2 参考实践 E261 关于用阈值探测器测定快中子注量率的一般性讨论。 5.3 钛具有良好的物理强度，易于制造，具有优异的耐腐蚀性，熔化温度为1668 并且可以获得令人满意的纯度。 5.4 46 Sc的半衰期为83.787（16） 4. 天 ( 2. ) 这个 46 Sc衰变发射0.889271（2）MeV伽马99.98374（35） % 和能量为1.120537（3）MeV 99.97的第二伽马 （2） %的时间。 5.5 天然钛的推荐“代表性同位素丰度” ( 3. ) 是: 8.25 (3) % 46 钛 7.44 (2) % 47 钛 73.72 (2) % 48 钛 5.41 (2) % 49 钛 5.18 (2) % 50 钛 5.6 中子反应的放射性产物 47 Ti（n，p） 47 Sc（τ 1/2 =3.3485（9）d） ( 2. ) 和 48 Ti（n，p） 48 Sc（τ 1/2 =43.67小时）， ( 3. ) 可能会干扰分析 46 Sc。 5.7 污染物活性（例如， 65 锌和 182 Ta）可能干扰分析 46 Sc.见 7.1.2 和 7.1.3 有关 182 Ta和 65 Zn干扰。 5.8 46 钛和 46 Sc的热中子截面分别为0.59±0.18和8.0±1.0谷仓 ( 4. ) ; 因此，当辐照超过大于约2×10的热中子注量时 21 厘米 –2 ，应规定使用热中子屏蔽以防止 46 Sc或测量热中子注量率并计算燃耗。 5.9 图1 显示了国际反应堆剂量学和聚变文件IRDFF-II横截面图 ( 5. ) 钛的快中子反应与中子能的关系 46 Sc（即， 纳特 Ti（n，X） 46 Sc）。图中包括: 46 Ti（n，p）反应和 47 Ti（n，np:d）对 46 Sc产量，标准化per 纳特 使用自然丰度加权单个同位素贡献的Ti原子 ( 3. ) .该图仅用于说明目的，应用于指示 纳特 Ti（n，X） 46 Sc反应。参考指南 E1018 有关推荐的列表剂量学横截面的说明。 图2 比较 46 Ti（n，p） 46 Sc对当前实验数据库的反应 ( 6. , 7. ) . 图3 比较 47 Ti（n，np:d）对当前实验数据库的反应 ( 6. , 7. ) . 图1 SAND-II 640组直方图表示 纳特 Ti（n，X） 46 Sc横截面（使用自然丰度数据对每个元素Ti原子进行归一化），表示为 纳特 Ti（n，p） 46 Sc， 纳特 Ti（n，np） 46 Sc和 纳特 钛（n，d） 46 Sc横截面组件 图2 46 Ti（n，p） 46 Sc横截面（按同位素标准化 46 Ti原子），来自IRDFF-II，与EXFOR实验数据 图3 47 Ti（n，np:d） 46 Sc横截面（按同位素标准化 47 Ti原子），来自IRDFF-II，与EXFOR实验数据

1.1 This test method covers procedures for measuring reaction rates by the activation reaction nat Ti(n,X) 46 Sc. The “X” designation represents any combination of light particles associated with the production of the residual 46 Sc product. Within the applicable neutron energy range for fission reactor applications, this reaction is a properly normalized combination of three different reaction channels: 46 Ti(n,p) 46 Sc; 47 Ti(n, np) 46 Sc; and 47 Ti(n,d) 46 Sc. Note 1: The 47 Ti(n,np) 46 Sc reaction, ENDF-6 format file/reaction identifier MF=3, MT=28, is distinguished from the 47 Ti(n,d) 46 Sc reaction, ENDF-6 format file/reaction identifier MF=3/MT=104, even though it leads to the same residual product ( 1 ) . 2 The combined reaction, in the IRDFF-II library, has the file/reaction identifier MF=10/MT=5. Note 2: The cross section for the combined 47 Ti(n,np:d) reaction is relatively small for energies less than 12 MeV and, in fission reactor spectra, the production of the residual 46 Sc is not easily distinguished from that due to the 46 Ti(n,p) reaction. 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 10 9 cm –2 ·s –1 can be determined. However, in the presence of a high thermal-neutron fluence rate, 46 Sc 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. ====== Significance And Use ====== 5.1 Refer to Guide E844 for the selection, irradiation, and quality control of neutron dosimeters. 5.2 Refer to Practice 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 46 Sc has a half-life of 83.787 (16) 4 days ( 2 ) . The 46 Sc decay emits a 0.889271 (2) MeV gamma 99.98374 (35) % of the time and a second gamma with an energy of 1.120537 (3) MeV 99.97 (2) % of the time. 5.5 The recommended “representative isotopic abundances” for natural titanium ( 3 ) are: 8.25 (3) % 46 Ti 7.44 (2) % 47 Ti 73.72 (2) % 48 Ti 5.41 (2) % 49 Ti 5.18 (2) % 50 Ti 5.6 The radioactive products of the neutron reactions 47 Ti(n,p) 47 Sc (τ 1/2 = 3.3485 (9) d) ( 2 ) and 48 Ti(n,p) 48 Sc (τ 1/2 = 43.67 h), ( 3 ) might interfere with the analysis of 46 Sc. 5.7 Contaminant activities (for example, 65 Zn and 182 Ta) might interfere with the analysis of 46 Sc. See 7.1.2 and 7.1.3 for more details on the 182 Ta and 65 Zn interference. 5.8 46 Ti and 46 Sc have cross sections for thermal neutrons of 0.59 ± 0.18 and 8.0 ± 1.0 barns, respectively ( 4 ) ; therefore, when an irradiation exceeds a thermal-neutron fluence greater than about 2 × 10 21 cm –2 , provisions should be made to either use a thermal-neutron shield to prevent burn-up of 46 Sc or measure the thermal-neutron fluence rate and calculate the burn-up. 5.9 Fig. 1 shows a plot of the International Reactor Dosimetry and Fusion File, IRDFF-II cross section ( 5 ) versus neutron energy for the fast-neutron reactions of titanium which produce 46 Sc (that is, nat Ti(n,X) 46 Sc). Included in the plot is the 46 Ti(n,p) reaction and the 47 Ti(n,np:d) contributions to the 46 Sc production, normalized per nat Ti atom with the individual isotopic contributions weighted using the natural abundances ( 3 ) . This figure is for illustrative purposes only and should be used to indicate the range of response of the nat Ti(n,X) 46 Sc reaction. Refer to Guide E1018 for descriptions of recommended tabulated dosimetry cross sections. Fig. 2 compares the cross section for the 46 Ti(n,p) 46 Sc reaction to the current experimental database ( 6 , 7 ) . Fig. 3 compares the cross section for the 47 Ti(n,np:d) reaction to the current experimental database ( 6 , 7 ) . FIG. 1 SAND-II 640-Group Histogram Representation of the nat Ti(n,X) 46 Sc Cross Section (Normalized per Elemental Ti Atom Using Natural Abundance Data), Represented By the Sum of the nat Ti(n,p) 46 Sc, nat Ti(n,np) 46 Sc, and nat Ti(n,d) 46 Sc Cross Section Components FIG. 2 46 Ti(n,p) 46 Sc Cross Section (Normalized per Isotopic 46 Ti Atom), from IRDFF-II, with EXFOR Experimental Data FIG. 3 47 Ti(n,np:d) 46 Sc Cross Section (Normalized per Isotopic 47 Ti Atom), from IRDFF-II, with EXFOR Experimental Data