论文标题
放射性衰减
Radioactive Decay
论文作者
论文摘要
不稳定原子核的放射性衰减导致以伽马射线光子和二级颗粒（电子，正电子）形式解放核结合能。然后，他们的能量在物质周围充满活力。不稳定的核是在核反应中形成的，核反应可能发生在恒星内部或爆炸的热极端和浓密的极端情况下，或者发生在宇宙射线碰撞中。在高能天文学中，放射性同位素衰减的特征性伽马射线线的直接观察是研究宇宙核合成及其来源过程的重要工具，以及从这种核合成来源中追踪射流的流量。这些观察结果为放射性能量沉积物的间接观察提供了有价值的补充，例如光学中超新星光的测量。在这里，我们介绍了天体物理环境中放射性衰变的基础知识，以及伽马射线线如何揭示有关恒星内部的细节，有关恒星表面或整个恒星的爆炸以及指导核合成灰烬流动和冷却的星际中等过程的爆炸。我们解决了$^{56} $ ni，$^{44} $ ti，$^{26} $ al，$^{26} $ al，$^{60} $ fe，$^{22} $ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na，$ na} $等放射性发散。
Radioactive decay of unstable atomic nuclei leads to liberation of nuclear binding energy in the forms of gamma-ray photons and secondary particles (electrons, positrons); their energy then energises surrounding matter. Unstable nuclei are formed in nuclear reactions, which can occur either in hot and dense extremes of stellar interiors or explosions, or from cosmic-ray collisions. In high-energy astronomy, direct observations of characteristic gamma-ray lines from the decay of radioactive isotopes are important tools to study the process of cosmic nucleosynthesis and its sources, as well as tracing the flows of ejecta from such sources of nucleosynthesis. These observations provide a valuable complement to indirect observations of radioactive energy deposits, such as the measurement of supernova light in the optical. Here we present basics of radioactive decay in astrophysical context, and how gamma-ray lines reveal details about stellar interiors, about explosions on stellar surfaces or of entire stars, and about the interstellar-medium processes that direct the flow and cooling of nucleosynthesis ashes once having left their sources. We address radioisotopes such as $^{56}$Ni, $^{44}$Ti, $^{26}$Al, $^{60}$Fe, $^{22}$Na, $^{7}$Be, and also how characteristic gamma-ray emission from the annihilation of positrons is connected to these.
