Ionization of Atomic Hydrogen by Low Energy Antiprotons

电离是天体物理和技术等离子体以及地球大气层中分子解离的一个重要过程。技术等离子体越来越多地用于材料的工业处理，特别是影响其表面性质，并且广泛用于半导体工业。氢同位素的受控等离子体聚变产生的能量为我们提供了一种“清洁”能源的可能性，以取代化石燃料，并缓解当前发电站排放的二氧化碳所导致的全球变暖。反质子对最简单原子（氢或其同位素氘）的电子去除或电离截面是目前相当感兴趣的。这是检验理论的最简单的碰撞系统，只有一个活跃的电子，因为反质子不能捕获电子，在碰撞后检测到氢离子与反质子重合是电离过程的标志。我们将在实验上从未达到的低能量范围内测量反质子碰撞电离氢原子的截面。我们对这样一个简单的三体系统中电离机制的理解应该使当前的理论模型向前迈出重要的一步。对电离的坚定的理论理解对于上述应用非常重要，因为理论通常用于为模拟提供输入，以及在难以甚至不可能进行专门实验的物理情况下解释观测结果。

Ionization is an important process in astrophysical and technological plasmas and in the dissociation of molecules in the Earth's atmosphere. Technological plasmas are increasingly used in industrial processing of materials, particularly to affect their surface properties, and are widely used in the semiconductor industry. Energy from controlled plasma fusion of hydrogen isotopes presents us with the possibility of a 'clean' energy source to replace fossil fuels and to alleviate global warming resulting from carbon dioxide emissions from current generation power stations.The cross section for electron removal or ionization of the simplest atom (hydrogen, or its isotope deuterium) by antiprotons is currently of considerable interest. This is the simplest collision system for testing theory with only one active electron and, since the antiproton cannot capture an electron, the detection of a hydrogen ion in coincidence with an antiproton after the collision is a signature of the ionization process. We will measure the cross sections for ionization of atomic hydrogen by antiproton impact at low energies, in a range never before accessed experimentally. Our understanding of the ionization mechanism in such a simple three-body system should enable an important step forward in current theoretical models.A firm theoretical understanding of ionization is important to the applications mentioned above, as theory is often used to provide input to simulations and in the interpretation of observations in physical situations where dedicated experiments are difficult, or even impossible...