论文标题
铍同位素组成和银河宇宙射线传播
Beryllium isotopic composition and Galactic cosmic ray propagation
论文作者
论文摘要
铍核的同位素组成及其能量依赖性编码有关星系中宇宙射线传播的基本重要性的信息。 The effects of decay on the spectrum of the unstable beryllium--10 isotope can be described introducing the average survival probability $P_{\rm surv} (E_0)$ that can inferred from measurements of the isotopic ratio Be10/Be9 if one has sufficiently good knowledge of the nuclear fragmentation cross sections that determine the isotopic composition of beryllium nuclei at injection.然后可以用传播参数（例如宇宙射线平均年龄）来解释平均生存概率，从而采用了银河传播的理论框架。最近，AMS02合作介绍了铍同位素组合物的初步测量，该测量将观测值扩展到较小的错误范围（$ e_0 \ simeq 0.7 $ -12 GEV/N）。在这项工作中，我们讨论了可以从初步AMS02数据推断出的平均生存概率，采用了公共可用的核碎片横截面模型，并解释了简单扩散模型的框架中的结果，这项研究表明，衰减的效果比预测更慢，导致平均宇宙射线射线年龄增加能量，而随着能量的增加。另一种可能性是，宇宙射线年龄分布比现在通常被接受的模型更广泛，这表明银河限制体积具有非微不足道的结构，并且由延伸的内部晕圈形成。
The isotopic composition of beryllium nuclei and its energy dependence encode information of fundamental importance about the propagation of cosmic rays in the Galaxy. The effects of decay on the spectrum of the unstable beryllium--10 isotope can be described introducing the average survival probability $P_{\rm surv} (E_0)$ that can inferred from measurements of the isotopic ratio Be10/Be9 if one has sufficiently good knowledge of the nuclear fragmentation cross sections that determine the isotopic composition of beryllium nuclei at injection. The average survival probability can then be interpreted in terms of propagation parameters, such as the cosmic ray average age, adopting a theoretical framework for Galactic propagation. Recently the AMS02 Collaboration has presented preliminary measurements of the beryllium isotopic composition that extend the observations to a broad energy range ($E_0 \simeq 0.7$-12 GeV/n) with small errors. In this work we discuss the average survival probability that can be inferred from the preliminary AMS02 data, adopting publically available models of the nuclear fragmentation cross sections, and interpret the results in the framework of a simple diffusion model, This study shows that the effects of decay decrease more slowly than the predictions, resulting in an average cosmic ray age that increases with energy. An alternative possibility is that the cosmic ray age distribution is broader than in the models that are now commonly accepted, suggesting that the Galactic confinement volume has a non trivial structure and is formed by an inner halo contained in an extended one.
