用激光驱动的中子源测量中子共振传输光谱的形状分析演示
Mitsuo Koizumi1, Fumiaki Ito2,3, Jaehong Lee2
1Integrated Support Center for Nuclear Nonproliferation and Nuclear Security, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki, 319-1195, Japan. koizumi.mitsuo@jaea.go.jp.
Scientific reports
|September 19, 2024
概括
研究人员成功地使用激光驱动的中子源 (LDNS) 进行了中子共振传输分析 (NRTA). 这一进步使得使用脉冲中子束进行非破坏性材料表征,克服噪声和有限镜头的挑战.
科学领域:
- 核物理 核物理 核物理
- 材料科学 材料科学 材料科学
- 激光与等离子体相互作用
背景情况:
- 激光驱动中子源 (LDNS) 为各种应用提供强烈的短脉冲中子束.
- 中子共振传输分析 (NRTA) 是一种关键的非破坏性技术,用于材料核素的识别和量化.
- 以前的NRTA方法主要依赖于传统的中子源.
研究的目的:
- 为了证明使用激光驱动中子源 (LDNS) 执行NRTA的可行性.
- 为了克服与LDNS相关的挑战,例如有限的激光拍摄和高背景噪声.
- 建立一种使用先进中子源进行非破坏性材料分析的新方法.
主要方法:
- 在大阪大学激光工程研究所使用LDNS.
- 采用一个时间门的化玻璃闪中子探测器来捕获传输光谱.
- 记录每个激光射击的输出波形,并使用计数方法进行离线分析.
- 应用了REFIT程序的最小平方核共振配件来分析获得的光谱.
主要成果:
- 通过使用LDNS成功获得了高分辨率的共振传输频谱.
- 通过光谱分析和模拟,确定了与特定核化物 (例如,-238和-232) 相关的独特共振.
- 证明了使用专用探测器减少电磁噪声和辐射闪光的影响的能力.
结论:
- 该研究证实了NRTA与LDNS的成功实施.
- 这种方法为非破坏性面积密度材料表征提供了可行的途径.
- 基于LDNS的NRTA为各种科学和工程领域的材料分析开辟了新的可能性.
相关概念视频
01:23Atomic Spectroscopy: Absorption, Emission, and Fluorescence
823
Atomic spectroscopy is a vital tool in elemental analysis, both qualitatively and quantitatively. It can be broadly divided into optical spectroscopy, mass spectroscopy, and X-ray spectroscopy methods. The optical spectroscopic methods are atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and atomic fluorescence spectroscopy (AFS). The first step in all three methods is atomization, where the solid, liquid, or solution-phase samples are converted into gas-phase atoms and...
823
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
777
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
777
01:05Atomic Nuclei: Magnetic Resonance
638
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
638
01:14NMR Spectrometers: Resolution and Error Correction
678
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
678
01:12Double Resonance Techniques: Overview
191
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
191
01:22Atomic Emission Spectroscopy: Instrumentation
343
The instrumentation of atomic emission spectrometry (AES) involves various components, including atomization devices that convert samples into gas-phase atoms and ions. There are two main types of atomization devices: continuous and discrete atomizers. Continuous atomizers, like plasmas and flames, introduce samples in a constant stream, while discrete atomizers inject individual samples using syringes or autosamplers. The most common discrete atomizer is the electrothermal atomizer.
343