Top-level physics requirements and simulated performance of the MRSt on the National Ignition Facility

The time-resolving Magnetic Recoil Spectrometer (MRSt) for the National Ignition Facility (NIF) has been identified by the US National Diagnostic Working Group as one of the transformational diagnostics that will reshape the way inertial confinement fusion (ICF) implosions are diagnosed. The MRSt will measure the time-resolved neutron spectrum of an implosion, from which the time-resolved ion temperature, areal density, and yield will be inferred. Top-level physics requirements for the MRSt were determined based on simulations of numerous ICF implosions with varying degrees of alpha heating, P2 asymmetry, and mix. Synthetic MRSt data were subsequently generated for different configurations using Monte–Carlo methods to determine its performance in relation to the requirements. The system was found to meet most requirements at current neutron yields at the NIF. This work was supported by the DOE and LLNL.

用于国家点火装置（National Ignition Facility，NIF）的时间分辨磁反冲谱仪（time-resolving Magnetic Recoil Spectrometer，MRSt）已被美国国家诊断工作组认定为将重塑惯性约束聚变（inertial confinement fusion，ICF）内爆诊断方式的变革性诊断工具之一。MRSt将测量内爆的时间分辨中子能谱，从中可推导出时间分辨的离子温度、面密度及产额。MRSt的顶层物理需求基于对具有不同程度阿尔法加热、P2不对称性及混合现象的大量ICF内爆模拟而确定。随后，利用蒙特卡罗方法针对不同配置生成合成MRSt数据，以评估其相对于上述需求的性能。结果表明，该系统在NIF当前中子产额条件下可满足大部分需求。本工作得到美国能源部（DOE）与劳伦斯利弗莫尔国家实验室（LLNL）的支持。