The processing code SPECTRA-PKA produces energy spectra of primary atomic recoil events (or primary knock-on atoms, PKAs) for any material composition exposed to an irradiation spectrum. Such evaluations are vital inputs for simulations aimed at understanding the evolution of damage in irradiated material, which is generated in cascade displacement events initiated by PKAs. These PKA spectra present the full complexity of the input (to SPECTRA-PKA) nuclear data-library evaluations of recoil events. However, the commonly used displacements per atom (dpa) measure, which is an integral measure over all possible recoil events of the displacement damage dose, is still widely used and has many useful applications – as both a comparative and correlative quantity. This paper describes the methodology employed that allows the SPECTRA-PKA code to evaluate dpa rates using the energy-dependent recoil (PKA) cross section data used for the PKA distributions. This avoids the need for integral displacement kerma cross sections and also provides new insight into the relative importance of different reaction channels (and associated different daughter residual and emitted particles) to the total integrated dpa damage dose. Results are presented for Fe, Ni, W, and SS316. Fusion dpa rates are compared to those in fission, highlighting the increased contribution to damage creation in the former from high-energy threshold reactions.

处理代码SPECTRA-PKA会为暴露于辐照光谱的任何材料成分生成一次原子反冲事件（或一次撞击原子，PKA）的能谱。这样的评估对于模拟是至关重要的输入，旨在了解受PKA引发的级联位移事件中所产生的辐照材料损伤的演变。这些PKA频谱显示了反冲事件输入（至SPECTRA-PKA）核数据库评估的全部复杂性。但是，常用的每原子位移（dpa）量度是位移损害剂量所有可能的后坐力事件的不可或缺的量度，仍被广泛使用并具有许多有用的应用–作为比较量和相关量。本文介绍了允许SPECTRA-PKA代码使用用于PKA分布的依赖于能量的后坐力（PKA）横截面数据评估dpa率的方法。这避免了对整体位移比释动能横截面的需要，并且还提供了对不同反应通道（以及相关的不同子残差和发射颗粒）相对于总积分dpa损伤剂量的相对重要性的新见解。给出了Fe，Ni，W和SS316的结果。将熔合dpa速率与裂变中的dpa速率进行了比较，突显了高能阈值反应对前者造成损伤的贡献增加。这避免了对整体位移比释动能横截面的需要，并且还提供了对不同反应通道（以及相关的不同子残差和发射颗粒）相对于总积分dpa损伤剂量的相对重要性的新见解。给出了Fe，Ni，W和SS316的结果。将熔合dpa速率与裂变中的dpa速率进行了比较，突显了高能阈值反应对前者造成损伤的贡献增加。这避免了对整体位移比释动能横截面的需要，并且还提供了对不同反应通道（以及相关的不同子残差和发射颗粒）相对于总积分dpa损伤剂量的相对重要性的新见解。给出了Fe，Ni，W和SS316的结果。将熔合dpa速率与裂变中的dpa速率进行比较，突显了高能阈值反应对前者造成损伤的贡献增加。