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18F abundance and the 18F(p,g)19Ne Reaction

18F 丰度和 18F(p,g)19Ne 反应

基本信息

批准号：
ST/H001883/1
负责人：
Alison Laird
金额：
$ 0.91万
依托单位：
University of York
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=ST%2FH001883%2F1
关键词：
18F abundance 19Ne Reaction

项目摘要

Nuclear astrophysics is one of the many applications of nuclear physics and arguably one of the most exciting. It tries to explain where all the elements around us, the oxygen in the air, the iron in our blood, the silicon in computer chips, come from. Where and how were they formed? On top of this, nuclear astrophysics tries to understand how nuclear reactions affect the life and death of all stars. How do such tiny things influence such massive objects as stars? Most stars get their energy by burning stable elements, such as the carbon and oxygen we are familiar with, over long periods of time. The energy is produced by nuclear reactions, turning one element into another. However, not all types of carbon, for example, are the same. Different types have different numbers of neutrons (but the same number of protons) and are called isotopes. Some isotopes of an element are unstable or radioactive and will change or decay into a different element, after a certain amount of time. In some stars which are very hot, the nuclear reactions happen so quickly that unstable isotopes will react with other isotopes before they have time to decay. Often, these hot stars will explode in spectacular displays of stellar fireworks, such as novae and supernovae. So to understand these exploding stars we need to be able to study the nuclear reactions with unstable isotopes that play a role. Astronomers can study these exploding stars by looking at the light that shines from them. From this light they can tell what elements were produced in the explosion and this gives nuclear physicists information on which nuclear reactions could be important. When certain unstable isotopes are produced, they decay and give off a particular type of light at very high energies called gamma rays. If these gamma rays are seen, then we know, not only that a particular element was produced, but also that it was a particular isotope and by knowing how far away the star is, we also know how much was produced. Scientists can then compare these observations with the predictions of computer models to see if we understand how these exploding stars work. These models need information on how quickly these unstable isotopes are created and destroyed by nuclear reactions and that is where the nuclear physics comes in. In the last few years, advances in technology have allowed scientists to accelerate these short-lived unstable istopes so that they can be used to study these reactions. Laboratories have been built to provide such unstable beams for studies and new laboratories are being developed that can produce more variety of unstable beams and higher intensities. One such laboratory is at TRIUMF in Vancouver, in Canada and is called ISAC. The proposed research programme will use the beams available at ISAC to study one of these special isotopes, 18F. We will study how quickly this isotope is destroyed in such stellar explosions by different nuclear reactions.

核天体物理学是核物理学的众多应用之一，也可以说是最令人兴奋的应用之一。它试图解释我们周围的所有元素，空气中的氧气，血液中的铁，电脑芯片中的硅，都是从哪里来的。它们是在哪里以及如何形成的？除此之外，核天体物理学试图了解核反应如何影响所有恒星的生与死。如此微小的物体是如何影响像恒星这样巨大的物体的呢？大多数恒星通过长时间燃烧稳定的元素（如我们熟悉的碳和氧）获得能量。能量是由核反应产生的，将一种元素转化为另一种元素。然而，并非所有类型的碳都是相同的。不同的类型有不同数量的中子（但相同数量的质子），被称为同位素。一种元素的某些同位素是不稳定的或放射性的，在一定时间后会变化或衰变成另一种元素。在一些非常热的恒星中，核反应发生得如此之快，以至于不稳定的同位素在衰变之前就会与其他同位素发生反应。通常，这些炽热的恒星会爆发出壮观的恒星烟花，如新星和超新星。所以要了解这些爆炸的恒星我们需要研究不稳定同位素的核反应。天文学家可以通过观察这些爆炸的恒星发出的光来研究它们。从这种光中，他们可以知道爆炸中产生了什么元素，这给了核物理学家关于哪些核反应可能是重要的信息。当某些不稳定的同位素产生时，它们会衰变并发出一种特殊类型的光，这种光具有非常高的能量，称为伽马射线。如果这些伽马射线被观测到，我们不仅知道产生了一种特定的元素，而且知道它是一种特定的同位素，通过知道星星有多远，我们也知道产生了多少。然后，科学家可以将这些观测结果与计算机模型的预测进行比较，看看我们是否理解这些爆炸恒星的工作原理。这些模型需要关于这些不稳定同位素在核反应中产生和破坏的速度的信息，这就是核物理学的作用。在过去的几年里，技术的进步使科学家们能够加速这些短暂的不稳定同位素，以便它们可以用来研究这些反应。已经建立了实验室来提供这种不稳定光束用于研究，并且正在开发新的实验室，可以产生更多种类的不稳定光束和更高的强度。其中一个实验室位于加拿大温哥华的TRIUMF，名为ISAC。拟议的研究计划将使用ISAC现有的光束来研究这些特殊同位素之一，18F。我们将研究这种同位素在恒星爆炸中被不同的核反应破坏的速度。