GAIN - GAllium In the slow Neutron capture process

解释宇宙中重元素的起源是一个引人入胜的跨学科挑战。当我们观察太阳和地球上的元素时，我们看到的是恒星中元素生产的综合结果。从最轻的元素氢开始，通过碳和铁等元素，恒星可以产生直到铅甚至铀的所有元素。所有这些元素都是我们在地球上生活所必需的。我们的目标是通过实验室的核反应测量和大型计算机场的核合成模拟来再现元素的丰度。大多数比铁更重的元素是通过中子俘获反应产生的。原子由带正电荷的质子和不带电荷的中子的原子核组成。原子核可以俘获中子，从而增加它的质量。在一个或多个中子俘获后，原子核可能会变得不稳定，中子将转化为质子。有了额外的质子，原子属于下一个更重的元素。慢中子捕获过程发生在比太阳重8倍以上的大质量恒星中。原子核捕获中子的时间尺度为几年。重元素是经过一万年的时间形成的。镓元素就是在这种情况下产生的。然而，没有关于产生或摧毁镓的中子俘获反应概率的准确数据。因此，GAIN项目旨在用两种互补的方法测量在镓上发生中子俘获反应的概率。这些数据将被用来运行核合成模拟，以量化不同恒星产生的镓的数量。随着银河系的演化，多代恒星相继产生了重元素，我们将获得准确的丰度，并将它们与我们太阳系中观测到的丰度进行比较。

The explanation of the origin of heavy elements in the Universe is a fascinating and interdisciplinary challenge. When we look at the Sun and the elements on Earth, we see the combined results of the production of elements in stars. Starting from the lightest element Hydrogen, passing elements like Carbon and Iron, stars can produce all the elements up to Lead or even Uranium. All these elements are necessary for our life on earth. We aim at reproducing the abundances of the elements by nuclear reaction measurements in the laboratory and nucleosynthesis simulations on large computer farms.Most of the elements heavier then Iron are produced by neutron capture reactions. An atom consists of a nucleus with positively charged protons and uncharged neutrons. A nucleus can capture a neutron and thereby increase its mass. After one or more neutron captures the nucleus may become unstable, and a neutron will convert into a proton. With the additional proton, the atom belongs to the next heavier element.The slow neutron capture process takes place in massive stars which are more than eight times heavier than our Sun. The nuclei capture neutrons at a time scale of a few years. The heavy elements are formed over a period of ten thousands of years. The element Gallium is produced in this scenario. However, accurate data for the probability of neutron capture reactions that produce or destroy Gallium are not available. The project GAIN therefore aims at measuring the probabilities of neutron capture reactions on Gallium with two complementary methods. The data will be used to run nucleosynthesis simulations to quantify the amount of Gallium which different stars produce. Following the evolution of the Galaxy, where many generations of stars successively produced heavy elements, we will obtain accurate abundances and compare them to the observed abundances in our Solar System.