元素样品识别用测探器的γ能量标定

Technique of detection with recognition of sample in the compound material based on the neutron capture reaction

  • 摘要: 矿山开采出的矿石往往内含多种元素,需要快速确定矿石中某种元素的成分及含量。热中子与样品中原子核发生俘获反应后形成激发态复核系统,会在极短时间内放射出不同能量及强度的特征γ射线(称之为γ射线特征指纹),表示为(n,γ)。通过检测特征γ射线的能量可以辨识样品中的元素种类,通过检测特定能量γ射线的强度得出样品中元素含量,俗称中子选矿。构建了Ce:GAGG晶体+PMT的γ射线探测器,分别利用1170 keV、1332 keV、4438 keV和2230 keV单能γ源,对探测器进行了γ能量标定,建立了γ能量和脉冲幅度分析器道数的线性关系,为探测器应用于矿山选矿提供了技术基础。

     

    Abstract:
    Background Ores mined from deposits often contain multiple elements. Rapid determination of the composition and concentration of specific elements is essential for mineral processing. Upon thermal neutron capture, target nuclei form excited compound nuclei, which promptly emit characteristic γ-rays with distinct energies and intensities—known as (n,γ) fingerprints. By measuring the γ-ray energies, the elemental species can be identified; by measuring the intensities, the corresponding concentrations can be quantified. This technique is commonly referred to as neutron-based ore sorting.
    Purpose This study aims to construct a detector system based on a Ce:GAGG crystal coupled with a photomultiplier tube (PMT) and to perform accurate γ-ray energy calibration for the system, thereby establishing a technical foundation for its application in on-site ore sorting in mines.
    Methods A detection module consisting of a Ce:GAGG scintillator and a PMT was developed. Energy calibration of the detector was carried out using kinds of single γ-ray peaks: 1170 keV,1332 keV,4438 keVand 2230 keV. These measurements established a linear relationship between γ-ray energy and multichannel analyzer (MCA) channel number.
    Results A reliable linear energy-to-channel calibration was achieved for the Ce:GAGG+PMT detector over the tested energy range. The calibration covers multiple characteristic peaks from both γ-ray and neutron sources, demonstrating the detector’s capability for accurate γ-ray energy determination.
    Conclusions The calibrated Ce:GAGG+PMT detector system provides a solid technical basis for its future application in neutron-based ore sorting in mining operations, enabling rapid, on-site elemental analysis of ores.

     

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