Collaborative Research: Neutron Interferometry Experiments for Nuclear Physics

该奖项是根据2009年美国复苏和再投资法案(公共法律111-5)资助的。中子干涉仪是一种利用自由中子的量子力学(QM)波状特性非常精确地测量物质的某些性质的设备。它的功能很像光干涉仪，只是它探测的是中子物质波而不是光波的干涉。慢中子(运动速度小于2000米/S)具有与固体中原子间距相当的QM波长，因此它与物质发生相干相互作用，即像波而不是粒子。当一个慢中子进入干涉仪时，它的QM波在一个完美的硅晶体中被衍射，并分裂成两个子波，每个子波采取不同的路径。这四个子波中的两个在后来的晶体中再次相遇，可能会相互干扰。干涉程度决定了在放置在干涉仪后面的中子探测器中探测到中子的概率。我们可以在干涉仪中放置一块物质，一个磁场或电场，甚至一个重力场，以使一个子波相对于另一个子波的相位移动，并改变这种干扰。这给出了关于中子在材料或场中相互作用的强度和性质的重要且通常是唯一的信息。我们使用中子干涉仪来研究对核物理重要的现象，如中子的内部电荷分布和中子与轻核的散射。研究生和本科生都参加了这个研究项目。除了学习中子干涉计量学，他们还接受了中子源研究的物理学和方法论方面的广泛教育，这为他们在学术界和工业界从事与中子科学有关的广泛职业做好了准备。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The neutron interferometer is a device that uses the quantum mechanical (QM) wave-like properties of free neutrons to measure certain properties of matter very precisely. It functions much like a light interferometer, except that it detects the interference of neutron matter waves rather than light waves. A slow neutron (moving less than 2000 m/s) has an associated QM wavelength comparable in size to the spacing of atoms in a solid, so it interacts with matter coherently, i.e. like a wave rather than a particle. When a slow neutron enters the interferometer, its QM wave is diffracted in a perfect silicon crystal and splits into two sub-waves, each taking a different path. Two of these four sub-waves meet again in a later crystal and can interfere with each other. The degree of interference determines the probability of detecting the neutron in a neutron detector placed behind the interferometer. We can place a piece of matter, a magnetic or electric field, or even a gravitational field inside the interferometer to shift the phase of one sub-wave relative to another and change this interference. This gives important and often unique information about the strength and nature of the neutron's interaction in the material or field. We use the neutron interferometer to study phenomena important for nuclear physics, such as the internal charge distribution of the neutron and the scattering of neutrons from light nuclei.Graduate and undergraduate students participate in this research program. In addition to learning the science of neutron interferometry, they are educated broadly in the physics and methodology of research at neutron sources, which prepares them for a wide range of careers related to neutron science in academia and industry.