Development of an RF Fragment Separator at the NSCL

NSCL 开发射频片段分离器

• 批准号: 0520930
• 负责人: Hendrik Schatz
• 金额: $ 25.12万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0520930&HistoricalAwards=false
• 关键词: Development; RF; Fragment; Separator; NSCL

Extremely unstable neutron deficient rare isotopes play a key role in explosive astrophysical events such as X-ray bursts and Novae. An understanding of the physics of these exotic nuclei is required to interpret in a quantitative way a range of new X-ray binary observations from space based X-ray observatories. This will pave the way to address the many open questions such as the mechanism behind burst oscillations, the origin of superbursts, and the nature of the underlying neutron star. Very neutron deficient nuclei serve also as unique probes of nuclear structure. They provide tests for the limits of nuclear existence, and they show unique decay modes such as one- and two-proton emission. In addition, neutron deficient nuclei include a special class of nuclei - isotopes with equal numbers of protons and neutrons. As protons and neutrons occupy the same shell model orbitals, many nuclear structure effects appear enhanced in such nuclei. This is particularly true for one of the most neutron deficient, classically doubly magic nuclei in nature, 100Sn. Doubly-magic nuclei, where both, protons and neutrons completely fill a nuclear shell, are of particular importance in nuclear physics and serve as benchmarks and beachheads for nuclear theories. The measurement of the decay properties of 100Sn is by many considered one of the "holy grails" of nuclear physics and would provide unique insights into the beta-decay of heavy nuclei. The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University has worldwide unique capabilities in producing extremely neutron deficient nuclei. This includes sufficient amounts of 100Sn to measure the properties of its decays,as well as all nuclei participating in the astrophysical rapid proton capture process in X-ray bursts. However, due to the nature of the projectile fragmentation mechanism used to create these nuclei, current experimental setups do not achieve the necessary beam purity.Many of the key experiments can therefore not be performed. We will build an RF Fragment Separator experiment, which will deflect unwanted rare isotope beam contaminants with an RF field, while transmitting the desired species. This device can be combined with existing experimental setups for decay and reaction studies and will allow a large group of graduate students and scientists to take full advantage of the production capabilities for neutron deficient beams at the NSCL to address fundamental questions in nuclear physics and astrophysics.

极不稳定的中子缺乏稀有同位素在爆炸性的天体物理事件（例如X射线爆发和Novae）中起着关键作用。 对这些外来核的物理学的理解必须以定量的方式解释一系列新的X射线二进制观测值，这些X射线二进制观测值来自基于空间的X射线观测值。这将为解决许多开放的问题铺平道路，例如爆发振荡背后的机制，超级爆炸的起源以及基础中子之星的性质。 非常中子缺乏核也是核结构的独特探针。它们提供了针对核存在限制的测试，并且显示了独特的衰减模式，例如单蛋白和两种蛋白发射。此外，中子缺乏核包括具有相等数量质子和中子的特殊类核 - 同位素。由于质子和中子占据了相同的壳模型轨道，因此在这种核中似乎增强了许多核结构效应。 对于自然界中最中子，最不足的魔术核之一，尤其如此，100sn是如此。双重魔术核，质子和中子都完全填充了核外壳，在核物理学中尤其重要，并且是核理论的基准和海滩。许多人认为核物理学的“圣杯”之一是对100SN的衰减特性的测量，并将为重核的β-末期提供独特的见解。密歇根州立大学的国家超导回旋实验室（NSCL）具有全球独特的能力，可产生极中子缺乏核。这包括足够数量的100sn来测量其衰减的性质，以及所有参与X射线爆发中天体物理快速质子捕获过程的核。 但是，由于用于创建这些核的弹丸碎片机制的性质，当前的实验设置无法达到必要的束纯度。因此，无法执行关键实验的许多。 我们将构建一个RF片段分离器实验，该实验将在传输所需物种的同时将不需要的稀有同位素束污染物偏转。该设备可以与现有的衰减和反应研究的实验设置结合使用，并将允许大量的研究生和科学家充分利用NSCL中性不足光束的生产能力，以解决核物理和天体物理学中的基本问题。