NIF ETA Experiment

The NIF energy tuning assembly (ETA) experiment was designed to spectrally shape the NIF deuterium-tritium fusion neutron source into a thermonuclear and prompt fission neutron spectrum. The environment was modeled in MCNP5 with a full-scale NIF model and neutron flux covariance with SCALE Sampler with MAVRIC. The neutron flux was unfolded using measured activation products and the initial guess spectrum with covariance information. A highly enriched uranium sample was fielded in the experimental cavity of the ETA and fission products have been measured in the unique environment. (MCNP directory) Contains an MCNP5 model for ETA experiment with a surface source SSR (rssa) (SCALE Sampler and MAVRIC directory) Contains base input for SCALE MAVRIC with Sampler in 252 group structure with output lower triangular correlation matrix and neutron spectra related to experiment. The file outputs have been compressed into a Python pickle file which can be opened with: import pickle Datafiles=open('ETA_Fielded_Samples.pckl','rb') SampledData=pickle.load(Datafiles) Datafiles.close(). The file is a dictionary containing the response functions for each of the independent Sampler runs. (PNNL STAYSL directory) Contains libraries, input, and output for STAYSL unfold in 129-group structure (GEF directory) Contains General Observables of Fission code input and output for estimated fission products (Fission Product Experimental Data directory) Contains experimental data utilized to fit to expression to estimate fission products (Fission Products directory) Contains measured fission product data (Components) Contains isotopic and elemental analysis of components.

国家点火装置（National Ignition Facility, NIF）能量调谐组件（Energy Tuning Assembly, ETA）实验旨在将NIF的氘-氚聚变中子源谱形变为热核与瞬发裂变中子能谱。实验环境采用全尺寸NIF模型通过蒙特卡罗粒子输运程序5（Monte Carlo N-Particle 5, MCNP5）进行建模，并结合SCALE采样器（SCALE Sampler）与MAVRIC模块处理中子通量协方差。中子通量展开采用实测活化产物与带协方差信息的初始猜测能谱完成。实验中将高浓缩铀样品布设至ETA实验腔体内，并在该独特环境中完成了裂变产物的测量。（MCNP目录）包含针对ETA实验的MCNP5模型，其带有表面源SSR（rssa）；（SCALE采样器与MAVRIC目录）包含基于252群结构、搭配采样器的SCALE MAVRIC基础输入文件，其输出包含下三角相关矩阵以及与实验相关的中子能谱。所有文件输出已被压缩为Python pickle格式文件，可通过以下代码读取：
import pickle
Datafiles=open('ETA_Fielded_Samples.pckl','rb')
SampledData=pickle.load(Datafiles)
Datafiles.close()
该文件为字典格式，存储了各独立采样器运行对应的响应函数。（太平洋西北国家实验室（Pacific Northwest National Laboratory, PNNL）STAYSL目录）包含129群结构下STAYSL展开方法所需的库文件、输入与输出文件；（GEF目录）包含用于估算裂变产物的裂变通用可观测代码（General Observables of Fission, GEF）的输入与输出文件；（裂变产物实验数据目录）包含用于拟合表达式以估算裂变产物的实验数据；（裂变产物目录）包含实测裂变产物数据；（组件目录）包含组件的同位素与元素组成分析结果。