Nuclear Astrophysics with DRAGON

与 DRAGON 进行核天体物理学

• 批准号: 316176-2013
• 负责人: Ruiz, Chris
• 金额: $ 12.75万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=571824
• 关键词: Nuclear; Astrophysics; DRAGON

The DRAGON Recoil Separator remains the world's most advanced facility for making direct measurements of 'radiative nuclear capture' reactions, a very common type of nuclear fusion found in stars. Located at the ISAC radioactive beam facility at TRIUMF, the facility enables the study of reactions involving exotic short-lived nuclei and hydrogen and helium, of the type that are found in exotic stellar scenarios such as core-collapse supernovae, classical novae, type 1 X-ray bursts, as well as quiescent stellar environments. The origin of the chemical elements through stellar nucleosynthesis is one of the greatest scientific questions of our time, and although much progress has been made in the area over the last 50 years, the details of this nucleosynthesis remain unclear, especially for how the heaviest elements were formed. In order to understand nucleosynthesis in various kinds of stars, and their contribution to the distribution of the elements we see in the Galaxy today, we need to have good working models of these scenarios that we can compare with astronomical observations. A fundamental part of this understanding is to know the roles of all the nuclear reactions that take place in these scenarios; these reactions affect energy generation and the synthesis of heavy elements. Since theory is at this point inadequate in predicting the strengths of the vital nuclear reactions, laboratory measurement is the main means by which we can advance the nuclear physics aspects of the models. The DRAGON astrophysics research program may be summarized as follows: a campaign of measurements of nuclear reactions occurring in stars, with the aim of eliminating nuclear physics uncertainties in astrophysical models. The astronomical observations that depend on these reactions can therefore be directly compared to our astrophysical models providing a look into the deepest inner workings of these stars and explosions where nuclear, not atomic processes dominate. Such astronomical observations may include: gamma rays from ejected radioisotopes, isotopic ratios in dust grains formed in ejected matter, peak luminosity and light curve shapes of explosion events.

龙反冲分离器仍然是世界上最先进的设施，用于直接测量“辐射核捕获”反应，这是一种在恒星中发现的非常常见的核聚变类型。该设施位于TRIUMF的ISAC放射性束设施，能够研究涉及外来短寿命核和氢和氦的反应，这种反应在外来恒星情景中发现，如核心坍缩超新星、经典新星、1型X射线爆发以及静止恒星环境。 通过恒星核合成的化学元素的起源是我们这个时代最伟大的科学问题之一，尽管在过去的50年里在该领域取得了很大的进展，但这种核合成的细节仍然不清楚，特别是最重的元素是如何形成的。为了了解各种恒星的核合成，以及它们对我们今天在银河系中看到的元素分布的贡献，我们需要有这些场景的良好工作模型，我们可以与天文观测进行比较。这种理解的一个基本部分是了解在这些情景中发生的所有核反应的作用;这些反应影响能量的产生和重元素的合成。由于理论在这一点上不足以预测重要核反应的强度，实验室测量是我们可以推进模型的核物理方面的主要手段。 DRAGON天体物理学研究计划可以概括如下：一项测量恒星中发生的核反应的活动，目的是消除天体物理学模型中的核物理学不确定性。 因此，依赖于这些反应的天文观测可以直接与我们的天体物理模型进行比较，以了解这些恒星和爆炸的最深内部运作，其中核过程而不是原子过程占主导地位。这类天文观测可能包括：放射性同位素喷出的伽马射线、喷出物质中形成的尘埃颗粒的同位素比率、爆炸事件的峰值光度和光变曲线形状。