1.1 本试验方法描述了在轻水反应堆（LWR）应用中使用固态跟踪记录器（SSTR）进行中子剂量测定。这些应用从低中子注量扩展到高中子注量，包括高功率压力容器监测和试验反应堆辐照以及低功率基准场测量 ( 1 ) . 2 特别注意使用最先进的手动和自动轨道计数方法，以获得高绝对精度。强调了实际高注量高温轻水堆应用中的原位剂量测定。 1.2 该测试方法包括通过手动和自动方法进行的SSTR分析。为了获得期望的精度，所选择的轨道扫描方法对允许的轨道密度施加限制。典型地，在5至800000个轨道/cm的范围内获得良好的结果 2 并且在某些情况下已经证明了在较高轨道密度下的准确结果 ( 2 ) 径迹密度和其他因素限制了SSTR方法在高通量下的适用性。当测量10以上的中子注量（E>1 MeV）时，必须特别小心 16 n/cm 2 ( 3 ) . 1.3 存在低注量和高注量限制。这些限制将在第节中详细讨论 13 和 14 在参考文献中 ( 3- 5 ) . 1.4 SSTR观察提供了时间积分反应速率。因此，SSTR是真正的无源注量探测器。它们提供了剂量测定实验的永久记录，而不需要时间相关的校正，例如辐射监测器产生的衰变因子。 1.5 由于SSTR在微观水平上提供了时间积分反应速率的空间记录，因此它们可用于“精细-结构”测量。例如，同位素裂变率的空间分布可以用SSTR以非常高的分辨率获得。 1.6 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 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》中确立的国际公认的标准化原则制定的。 ======意义和用途====== 4.1 SSTR方法提供了每单位质量绝对裂变密度的测量。如果已知适当的中子谱平均裂变截面，则可以从这些基于SSTR的绝对裂变率观测结果推断出绝对中子注量。该方法对堆芯内辐射场的其他分量具有很高的区分性。伽马射线、β射线和其他轻度电离粒子在适当的LWR SSTR候选材料中不会产生可观察到的轨迹。然而，光裂变可能有助于观察到的裂变径迹密度，因此在不可忽略时应予以考虑。有关光裂变效应的更详细讨论，请参见 14.4 . 4.2 在这种测试方法中，SSTR与可裂变沉积物表面接触，并记录中子-诱发裂变碎片。通过表面质量密度（μ g/cm 2 ）以及采用允许范围的轨迹密度（从大约1个事件/cm 2 最多10个 5 事件/cm 2 对于手动扫描），覆盖至少16个数量级的总注量灵敏度范围是可能的，从大约10个数量级。 2 n/cm 2 高达5 × 10 18 n/cm 2 裂变径迹密度的允许范围比中引用的用光学显微镜进行高精度手动扫描工作的径迹密度范围更宽 1.2 特别地，存在自动和半自动方法，其拓宽了手动光学显微镜可用的常规轨迹密度范围。在这个更广泛的轨道密度区域，在非常低的轨道密度和轨道桩下减少计数统计的影响-在非常高的磁道密度下的向上校正对于高精度的工作可能存在固有的限制。自动扫描技术在第节中描述 11 . 4.3 对于剂量测定应用，可以通过改变用于裂变沉积的核素来选择性地强调中子谱的不同能量区域。 4.4 可以将SSTR直接用于中子剂量测定，如中所述 4.1 或者通过在基准中子场中暴露来获得复合中子探测效率。必须知道该基准场中的注量和频谱平均截面。此外，由于光谱偏离用于校准的基准场光谱，在其他中子场中的应用可能需要调整。无论如何，必须强调的是，SSTR裂变密度测量可以完全独立于任何交叉-截面标准 ( 6 ) 因此，对于某些应用，该测试方法的独立性不应受到损害。另一方面，存在许多实际应用，其中该因素不重要，使得基准场校准将是完全合适的。

1.1 This test method describes the use of solid-state track recorders (SSTRs) for neutron dosimetry in light-water reactor (LWR) applications. These applications extend from low neutron fluence to high neutron fluence, including high-power pressure vessel surveillance and test reactor irradiations as well as low-power benchmark field measurement ( 1 ) . 2 Special attention is given to the use of state-of-the-art manual and automated track counting methods to attain high absolute accuracies. In-situ dosimetry in actual high-fluence high-temperature LWR applications is emphasized. 1.2 This test method includes SSTR analysis by both manual and automated methods. To attain a desired accuracy, the track scanning method selected places limits on the allowable track density. Typically, good results are obtained in the range of 5 to 800 000 tracks/cm 2 and accurate results at higher track densities have been demonstrated for some cases ( 2 ) . Track density and other factors place limits on the applicability of the SSTR method at high fluences. Special care must be exerted when measuring neutron fluences (E > 1 MeV) above 10 16 n/cm 2 ( 3 ) . 1.3 Low-fluence and high-fluence limitations exist. These limitations are discussed in detail in Sections 13 and 14 and in Refs ( 3- 5 ) . 1.4 SSTR observations provide time-integrated reaction rates. Therefore, SSTRs are truly passive fluence detectors. They provide permanent records of dosimetry experiments without the need for time-dependent corrections, such as decay factors that arise with radiometric monitors. 1.5 Since SSTRs provide a spatial record of the time-integrated reaction rate at a microscopic level, they can be used for “fine-structure” measurements. For example, spatial distributions of isotopic fission rates can be obtained at very high resolution with SSTRs. 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 ====== 4.1 The SSTR method provides for the measurement of absolute fission density per unit mass. Absolute neutron fluence can then be inferred from these SSTR-based absolute fission rate observations if an appropriate neutron spectrum average fission cross section is known. This method is highly discriminatory against other components of the in-core radiation field. Gamma rays, beta rays, and other lightly ionizing particles do not produce observable tracks in appropriate LWR SSTR candidate materials. However, photofission can contribute to the observed fission track density and should therefore be accounted for when non-negligible. For a more detailed discussion of photofission effects, see 14.4 . 4.2 In this test method, SSTRs are placed in surface contact with fissionable deposits and record neutron-induced fission fragments. By variation of the surface mass density (μg/cm 2 ) of the fissionable deposit as well as employing the allowable range of track densities (from roughly 1 event/cm 2 up to 10 5 events/cm 2 for manual scanning), a range of total fluence sensitivity covering at least 16 orders of magnitude is possible, from roughly 10 2 n/cm 2 up to 5 × 10 18 n/cm 2 . The allowable range of fission track densities is broader than the track density range for high-accuracy manual scanning work with optical microscopy cited in 1.2 . In particular, automated and semi-automated methods exist that broaden the customary track density range available with manual optical microscopy. In this broader track density region, effects of reduced counting statistics at very low track densities and track pile-up corrections at very high track densities can present inherent limitations for work of high accuracy. Automated scanning techniques are described in Section 11 . 4.3 For dosimetry applications, different energy regions of the neutron spectrum can be selectively emphasized by changing the nuclide used for the fission deposit. 4.4 It is possible to use SSTRs directly for neutron dosimetry as described in 4.1 or to obtain a composite neutron detection efficiency by exposure in a benchmark neutron field. The fluence and spectrum average cross section in this benchmark field must be known. Furthermore, application in other neutron fields may require adjustments due to spectral deviation from the benchmark field spectrum used for calibration. In any event, it must be stressed that the SSTR fission density measurements can be carried out completely independent of any cross-section standards ( 6 ) . Therefore, for certain applications, the independent nature of this test method should not be compromised. On the other hand, many practical applications exist wherein this factor is of no consequence so that benchmark field calibration would be entirely appropriate.