标题： ANTARES冷中子束线的时间分辨中子成像 显示英文标题

标题： Time-resolved neutron imaging at ANTARES cold neutron beamline

摘要： 在X射线无损检测中，嵌入致密、重（或高Z）基质中的轻元素对比度很小，其结构细节难以显现。 另一方面，中子成像为这些情况提供了解决方案，特别是对于含氢材料，这是由于氢的大中子散射截面以及中子截面与原子序数的不相关依赖性。 目前大多数中子成像实验是针对静态物体进行的，主要是由于中子束线设施的通量强度有限，有时也由于探测器的限制。 然而，一些应用需要研究动态现象，现在可以在一些高强度束线如FRM-II反应堆最近重建的ANTARES束线上进行。 本文展示了时间分辨成像在重复过程中的能力，其中可以同时成像过程的不同阶段，并对多个周期进行积分。 使用了一种快速MCP/Timepix中子计数探测器来成像以10 Hz频率运行的模型蒸汽机内的水分布。 在<10分钟的积分时间内，测量了水的量随循环时间的变化，具有亚毫米的空间分辨率，从而展示了时间分辨中子照相术在未来应用中的能力。 还使用飞行时间（TOF）技术结合高分辨率光束斩波器测量了ANTARES束线的中子能谱以及铁样品的透射谱。 我们的装置的能量分辨率在5 meV时为~0.8%，在25 meV时为~1.7%。 显示英文摘要

摘要： In non-destructive evaluation with X-rays light elements embedded in dense, heavy (or high-Z) matrices show little contrast and their structural details can hardly be revealed. Neutron radiography, on the other hand, provides a solution for those cases, in particular for hydrogenous materials, owing to the large neutron scattering cross section of hydrogen and uncorrelated dependency of neutron cross section on the atomic number. The majority of neutron imaging experiments at the present time is conducted with static objects mainly due to the limited flux intensity of neutron beamline facilities and sometimes due to the limitations of the detectors. However, some applications require the studies of dynamic phenomena and can now be conducted at several high intensity beamlines such as the recently rebuilt ANTARES beam line at the FRM-II reactor. In this paper we demonstrate the capabilities of time resolved imaging for repetitive processes, where different phases of the process can be imaged simultaneously and integrated over multiple cycles. A fast MCP/Timepix neutron counting detector was used to image the water distribution within a model steam engine operating at 10 Hz frequency. Within <10 minutes integration the amount of water was measured as a function of cycle time with a sub-mm spatial resolution, thereby demonstrating the capabilities of time-resolved neutron radiography for the future applications. The neutron spectrum of the ANTARES beamline as well as transmission spectra of a Fe sample were also measured with the Time Of Flight (TOF) technique in combination with a high resolution beam chopper. The energy resolution of our setup was found to be ~0.8% at 5 meV and ~1.7% at 25 meV.