Shape co-existence in neutron-rich A~110 nuclei

在每个原子的中心都有一个原子核，关于原子核如何运动的信息与许多领域相关，包括医学诊断，有时还包括治疗，核电等。因此，我们建立原子核在不同情况下如何反应的图像是很重要的。例如，为什么有些原子核是稳定的，或者，如果它们确实衰变，为什么它们以一种特定的方式衰变？为什么原子核会呈现不同的形状，又是什么力量驱使它们呈现这些形状？可能有6000种中子和质子的组合可以粘在一起形成原子核，这些原子核的寿命足够长，可以被观察到。其中只有大约300种存在于自然界中，我们对原子核及其性质的大部分知识来自于对这300种原子核的详细研究。因此，为了测试我们的核力模型，我们必须制造和研究新的系统。通常，当我们制造一个处于激发态的原子核时，它会在几分之一秒内衰变（通常是1除以10，后面有15个零）。有时，原子核会被困在一个特定的结构中，然后存活的时间超过十亿分之一秒。我们称这些态为同分异构体，本研究计划是寻找预测存在于重锆核中的这种态。实验的目标不仅仅是发现这些状态，一旦它们被发现，如果它们确实存在，我们建议测量它们的性质，并根据模型预测对它们进行测试。这种比较的结果将用于进一步完善模型，以便它们可以用来推断它们所开发的核之外的情况。因此，这些信息将使我们更清楚地了解原子核的行为，从而使我们能够最大限度地利用它们。

At the centre of every atom there is a nucleus and information about how nuclei behave is relevant to many areas, including medical diagnosis and sometimes therapy, nuclear power etc. Hence it is important that we build up a picture of how nuclei react under different circumstances. For example why are some nuclei stable or, if they do decay, why do they do so by a particular method? Why do nuclei take on different shapes and what are the forces which drive them to these shapes? There are possibly 6000 combinations of neutrons and protonswhich could stick together to form nuclei that would live long enough tobe observed. Of these only about 300 exist in nature and most of ourknowledge of nuclei and their properties comes from the detailedstudy of these 300. Hence in order to test our models of nuclear forces, we have to make and study new systems. Normally when we make a nucleus in an excited state, it decays within a fraction (typically about 1 divided by 10 with 15 noughts after it) of a second . Sometimes a nucleus gets stuck in one particular configuration which then lives for a time longer than 1 thousand millionth of a second. We call these states isomeric and this research proposal is to search for such states which are predicted to exist in the heavy zirconium nuclei. It is not just the finding of these states which is the experimental goal but once they are found, if indeed they do exist, we propose to measure their properties and test them against the model predictions. The results of this comparison will be used to further refine the models so that they can be used to extrapolate beyond the nuclei for which they were developed. This information will therefore give us a clearer view of how nuclei behave and hence will enable us to use them to their maximum potential.