Nuclear structure investigations using gamma-ray and electron spectroscopy

使用伽马射线和电子能谱研究核结构

• 批准号: 402878-2011
• 负责人: Garnsworthy, Adam
• 金额: $ 8.09万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=488201
• 关键词: Nuclear; structure; investigations; using; gamma

The building blocks of the world around us are atoms which are formed of a cloud of electrons orbiting a tiny, very dense core called the nucleus. This nucleus is formed of a collection of protons and neutrons. It is the aim of this research to help further our understanding of the interactions between the protons and neutrons within the nucleus. Inside a nucleus the protons tend to pair up with each other, and the neutrons also form pairs, in both cases with their spin quantum numbers coupled to zero. This is somewhat analogous to the electron pairs (Cooper pairs) in a superfluid. It is then the interaction between these pairs and the breaking of individual pairs which are the excitations we can observe in the laboratory. In the special case of nuclei with the same number of neutrons and protons, so called N=Z nuclei, another situation arrises where neutron-proton pairs can form. This special type of pair can couple the spins not just to zero but also to one and still obey the rules of quantum mechanics. The unique properties of these neutron-proton pairs and how similar they behave to the usual neutron-neutron or proton-proton pairs is still not fully understood. In the proposed research here we will produce a high energy beam of a N=Z nucleus at the ISAC facility of TRIUMF, Vancouver. This high energy beam will then undergo a nuclear reaction to form a hot, excited state. The TIGRESS detector will be used to observe the high energy form of light, called gamma rays, which are emitted as the nucleus cools down again after the reaction. In some special cases the nucleus cools down not by emitting a gamma ray but by emitting an atomic electron. The new SPICE spectrometer will be able to detect these electrons which can provide additional information to the gamma rays alone. In studying the energy and properties of the gamma rays or electrons we can investigate the interactions between the neutrons and protons inside the nucleus.

我们周围的世界是由原子组成的，原子是由电子云围绕一个微小的，非常密集的核心，称为原子核。这个原子核是由质子和中子集合而成的。这是这项研究的目的，以帮助我们进一步了解质子和中子之间的相互作用的核。在原子核内部，质子倾向于彼此成对，中子也会成对，在这两种情况下，它们的自旋量子数都耦合为零。这有点类似于超流体中的电子对（库珀对）。因此，这些电子对之间的相互作用和单个电子对的断裂，就是我们在实验室中可以观察到的激发。在中子和质子数相同的原子核的特殊情况下，即所谓的N=Z原子核，会出现另一种情况，即中子-质子对可以形成。这种特殊类型的对不仅可以将自旋耦合到零，还可以耦合到一，并且仍然遵守量子力学的规则。这些中子-质子对的独特性质以及它们与通常的中子-中子或质子-质子对的行为有多相似仍然没有完全理解。在这里提出的研究中，我们将在温哥华的TRIUMF的ISAC设施中产生N=Z核的高能束流。然后，这种高能束将经历核反应，形成热的激发态。TIGRESS探测器将用于观测高能形式的光，称为伽马射线，这些射线是在反应后原子核再次冷却时发射的。在某些特殊情况下，原子核冷却不是通过发射伽马射线，而是通过发射原子电子。新的SPICE光谱仪将能够检测到这些电子，这可以提供额外的信息，以单独的伽马射线。在研究伽马射线或电子的能量和性质时，我们可以研究原子核内中子和质子之间的相互作用。