高级检索

基于神经网络的原子核α衰变寿命研究

Predictions of Nuclear α-Decay Half-lives Using Neural Networks

  • 摘要: \alpha衰变寿命的研究对于深入揭示原子核结构与量子隧穿机制具有重要意义,同时也为新核素的发现、超重元素的预测以及核技术的相关应用提供了关键理论支撑。本文采用两种前馈式全连接神经网络模型对\alpha衰变寿命进行预测。模型ML1的输入包括质子数Z、中子数N、奇偶性系数\delta以及\alpha衰变能量Q_\alpha;在此基础上,模型ML2增加了最小角动量项l(l+1),两者在网络结构和超参数上保持一致,以便系统比较角动量对模型性能的影响。研究表明,ML1和ML2在预测\alpha衰变半衰期方面均表现出良好性能,与实验值的均方根偏差(RMS)分别为0.46和0.44个数量级,显著优于有限力程小液滴模型(FRDM)+Viola-Seaborg (VS)公式。此外,两种模型均能成功再现衰变子核位于闭壳区(如Z=82, N=126)附近核素的\alpha衰变寿命突变特征。由于实验中非零角动量\alpha衰变样本有限,尽管ML2引入了角动量项,但与ML1的RMS差异较小。说明在参数充足的神经网络中,角动量信息可能被其他参数优化所掩盖,导致其对预测精度的提升有限。

     

    Abstract: The study of \alpha-decay half-lives is of great significance for revealing nuclear structure and quantum tunneling mechanisms. It also provides essential theoretical support for the discovery of new nuclides, the prediction of superheavy elements, and various applications in nuclear technology. In this work, two feedforward fully connected neural network models are employed to predict \alpha-decay half-lives. Model ML1 takes the proton number Z, neutron number N, even-odd effect term \delta, and \alpha-decay energy Q_\alpha as inputs. Model ML2 extends ML1 by incorporating the minimum angular momentum term l(l+1). Both models share identical network architectures and hyperparameter settings, allowing a systematic comparison of the impact of angular momentum on model performance. The study shows that both ML1 and ML2 exhibit good predictive performance for \alpha-decay half-lives, with root-mean-square deviations (RMS) of 0.46 and 0.44 logarithmic units relative to the experimental values, respectively. These results are significantly better than those obtained with the finite-range droplet model (FRDM) combined with the Viola-Seaborg (VS) formula. In addition, both models are capable of successfully reproducing the sudden changes in \alpha-decay half-lives for nuclei located near shell closures, such as Z=82 and N=126. Due to the limited number of nonzero angular momentum \alpha-decay samples in the experimental data, although ML2 incorporates the angular momentum term, the RMS difference compared to ML1 is small. This indicates that in neural networks with sufficient parameters, the angular momentum information may be overshadowed by the optimization of other parameters, resulting in limited improvement in prediction accuracy.

     

/

返回文章
返回