Pulse Pile-up Correction by Particle Swarm Optimization with Double-layer Parameter Identification Model in X-ray Spectroscopy. - Yang Xiao-Feng; Huang Hong-Quan; Zeng Guo-Qiang; Ge Liang-Quan; Jiang Kai-ming; Gu Min; Hu Chuan-Hao; Lai Mao-Lin (J. Signal Process. Syst., 2022)