Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621999, People's Republic of China.
State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang, 621010, People's Republic of China.
Sci Rep. 2017 Mar 15;7:44070. doi: 10.1038/srep44070.
Due to quantum coherence, nanoparticles have very large cross sections when scattering with very cold or Ultracold Neutrons (UCN). By calculating the scattering cross section quantum mechanically at first, then treating the nanoparticles as classical objects when including the rotational effects, we can derive the associated energy transfer. We find that rotational effects could play an important role in slowing down UCN. In consequence, the slowing down efficiency can be improved by as much as ~40%. Since thermalization of neutrons with the moderator requires typically hundreds of collisions between them, a ~40% increase of the efficiency per collision could have a significant effect. Other possible applications, such as neutrons scattering with nano shells and magnetic particles,and reducing the systematics induced by the geometric phase effect using nanoparticles in the neutron Electric Dipole Moment (nEDM), are also discussed in this paper.
由于量子相干，纳米粒子在与极冷或超冷中子（UCN）散射时具有非常大的横截面。首先通过量子力学计算散射横截面，然后在包括旋转效应时将纳米粒子视为经典物体，我们可以得出相关的能量转移。我们发现旋转效应对减慢 UCN 可能起着重要作用。因此，减速效率可以提高约 40%。由于热中子与慢化剂之间的热化通常需要它们之间数百次碰撞，因此每次碰撞效率提高 40%可能会产生重大影响。本文还讨论了其他可能的应用，例如纳米壳与中子的散射、磁性粒子，以及使用纳米粒子在中子电偶极矩（nEDM）中减小由几何相位效应引起的系统偏差。
