LUNA核天体物理学的超灵敏束内gamma-ray光谱学

LUNA 3He（α，γ）7Be活化结果与早期测量和模型计算的比较

Comparison of the LUNA 3He(alpha,gamma)7Be activation results with earlier measurements and model calculations

最近，LUNA合作已经进行了高精度测量的3He（α，γ）7Be反应截面与激活和在线γ探测方法在前所未有的低能量。本文总结了用活化法所得到的结果。结果与以前的激活实验和零能量外推天体物理S因子确定使用不同的理论模型进行了比较。

Underground Measurements of Nuclear Reaction Cross-Sections Relevant to AGB Stars

Nuclear reaction cross sections are essential ingredients to predict the evolution of AGB stars and understand their impact on the chemical evolution of our Galaxy. Unfortunately, the cross sections of the reactions involved are often very small and challenging to measure in laboratories on Earth. In this context, major steps forward were made with the advent of underground nuclear astrophysics, pioneered by the Laboratory for Underground Nuclear Astrophysics (LUNA). The present paper reviews the contribution of LUNA to our understanding of the evolution of AGB stars and related nucleosynthesi…

LUNA: Status and Prospects

The essential ingredients of nuclear astrophysics are the thermonuclear reactions which shape the life and death of stars and which are responsible for the synthesis of the chemical elements in the Universe. Deep underground in the Gran Sasso Laboratory the cross sections of the key reactions responsible for the hydrogen burning in stars have been measured with two accelerators of 50 and 400 kV voltage right down to the energies of astrophysical interest. As a matter of fact, the main advantage of the underground laboratory is the reduction of the background. Such a reduction has allowed, for …

LUNA深地实验室中${}^{\mathsf{12}}\mathsf{C}(\mathsf{p},γ)$反应低能截面测量

Low-energy Cross Section Measurements of ${}^{\mathsf{12}}\mathsf{C}(\mathsf{p},γ)$ Deep Underground at LUNA

在LUNA低本底环境中，利用固体靶和HPGe谱学与活化计数两种互补技术测量12C(p,γ)反应低能截面，通过精确表征靶并监测其退化以减少系统误差。

天体物理中13C(α,n)16O反应直接截面测量的现状与未来方向

Status and future directions for direct cross-section measurements of the 13C(a,n)16O reaction for astrophysics

本文梳理了天体物理关键中子源反应13C(α,n)16O的直接截面测量现状，分析了LUNA等合作组的测量结果，提出了未来实验需覆盖宽能区、优化靶表征与效率测定、开展多道R矩阵分析等方向以提升低能外推约束精度。

A new approach to monitor 13C-targets degradation in situ for 13C(alpha,n)16O cross-section measurements at LUNA

Direct measurements of reaction cross-sections at astrophysical energies often require the use of solid targets able to withstand high ion beam currents for extended periods of time. Thus, monitoring target thickness, isotopic composition, and target stoichiometry during data taking is critical to account for possible target modifications and to reduce uncertainties in the final cross-section results. A common technique used for these purposes is the Nuclear Resonant Reaction Analysis (NRRA), which however requires that a narrow resonance be available inside the dynamic range of the accelerato…

Underground nuclear astrophysics: why and how

The goal of nuclear astrophysics is to measure cross sections of nuclear physics reactions of interest in astrophysics. At stars temperatures, these cross sections are very low due to the suppression of the Coulomb barrier. Cosmic ray induced background can seriously limit the determination of reaction cross sections at energies relevant to astrophysical processes and experimental setups should be arranged in order to improve the signal-to-noise ratio. Placing experiments in underground sites, however, reduces this background opening the way towards ultra low cross section determination. LUNA …

天体物理核反应中的原子效应

Atomic effects in astrophysical nuclear reactions

本文提出了两个描述天体物理能量下实验室核反应中出现的电子屏蔽效应的模型。第一个模型的双电子屏蔽能与最近LUNA的实验结果非常一致的破碎反应$% He3(He3,2p)He^{4}$，迄今为止，这违背了所有可用的理论模型。此外，多电子效应，提高实验室反应的CNO循环和其他先进的核燃烧阶段，也研究了通过的CNO-费米模型，推导出的分析公式，建立一个下限和上限的相关屏蔽能量。第二个模型的结果，这表明一个非常令人满意的兼容性与绝热近似的，预计将是特别有用的，在未来的实验中更准确地确定的CNO天体物理因子。

Progress of the Felsenkeller shallow-underground accelerator for nuclear astrophysics

Low-background experiments with stable ion beams are an important tool for putting the model of stellar hydrogen, helium, and carbon burning on a solid experimental foundation. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso, using a 0.4 MV accelerator. In the present contribution, the status of the project for a higher-energy underground accelerator is reviewed. Two tunnels of the Felsenkeller underground site in Dresden, Germany, are currently being refurbished for the installation of a 5 MV high-current Pelletron accelerator. Construction work is on …

α束入射氘气靶的中子感生本底及其对LUNA 2 H（α，γ）6Li反应研究的意义

Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

在标准大爆炸核合成中产生稳定同位素Li-6最近引起了人们的极大兴趣。最近对贫金属恒星的观测表明，宇宙学上的Li-6平台可能存在。如果这是真的，这个平台将是除了众所周知的Li-7丰度的Spite平台之外的另一个平台，并将指向Li-6的主要原始起源，与标准的大爆炸核合成计算结果相反。因此，必须重新审视大爆炸Li-6产生背后的核物理。大爆炸中Li-6的主要产生通道是2 H（alpha，gamma）6Li反应。目前的工作报告中，在一个高纯度的锗探测器，在一个新的研究，这种反应中遇到的中子诱导效应。实验中使用了意大利格兰萨索地下加速器LUNA的α束流和无窗氘气靶。一个低的中子通量是由高能氘弹性散射，随后，2 H（d，n）3 He反应。由于LUNA实验室中子本底极低，因此详细研究了2-3 MeV中子的弱通量对屏蔽良好的高纯锗探测器的影响。数据已采取在280和400千电子伏的α-束能量和比较也使用镅铍中子源。