基于卷积循环神经网络的核素识别方法研究

Research on nuclide identification method based on convolutional recurrent neural network

  • 摘要: 核素的准确识别是提高放射性监测水平的关键。为进一步提升放射性核素识别性能,研究了基于卷积神经网络(CNN)和循环神经网络(RNN)结合的核素识别方法。使用碘化钠能谱仪采集8种单一和混合放射性核素γ能谱数据,通过计算γ光子在不同能量下的概率密度,采用随机抽样的方法生成大量γ能谱训练数据,并对数据进行归一化处理,然后利用CNN提取输入能谱数据的特征向量,并将提取到的特征向量输入RNN进行训练,最后由激活函数输出核素分类结果。为验证CNN-RNN识别核素的准确性,与基于卷积神经网络(CNN)和长短时记忆神经网络(LSTM)核素识别方法进行比较分析,得出在测试集上LSTM能谱模型对单核素的识别准确率优于97.5%,混合核素的识别率优于92.31%,CNN和CNN-RNN能谱模型对单核素的识别准确率为100%,混合核素的识别率分别优于92.95%和97.44%。结果表明,CNN-RNN能谱模型在γ能谱放射性核素识别中表现更优,通过与仅用实测数据训练的神经网络模型相比,加入增强数据可提升模型的训练效率和泛化能力。

     

    Abstract:
    Background
    Accurate identification of radionuclides is the key to improving the level of radioactivity monitoring.
    Purpose
    To further enhance the performance of radionuclide identification, a method combining Convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) for radionuclide identification was studied.
    Methods
    Gamma-ray spectra data of eight single and mixed radioactive nuclides were collected using a sodium iodide spectrometer, and a large number of gamma-ray spectral training data were generated by calculating the probability density of gamma photons at different energy levels and using random sampling methods, followed by normalization of the data. The CNN was then used to extract feature vectors from the input spectral data, and these extracted feature vectors were fed into the RNN for training, with the final radionuclide classification results being output by the activation function.
    Results
    To verify the accuracy of the CNN-RNN method in identifying radionuclides, a comparative analysis was conducted with the radionuclide identification method based on CNN and Long Short-Term Memory Neural Network (LSTM). The results showed that the LSTM spectral model achieved a recognition accuracy rate of over 97.5% for single nuclides and over 92.31% for mixed nuclides on the test set, while the CNN and CNN-RNN spectral models achieved a recognition accuracy rate of 100% for single nuclides and recognition rates of over 92.95% and 97.44% for mixed nuclides, respectively.
    Conclusions
    The findings indicating that the CNN-RNN method performs better in gamma-ray spectral identification of radioactive nuclides. Compared with neural network models trained only on real-measured data, incorporating augmented data can improve the training efficiency and generalization ability of the models.

     

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