Figure 4. Pump-probe time delay prediction.

(a,b) Examples of the X-band transverse deflecting cavity (XTCAV) traces used to extract the delay values. The delay values are calculated by finding the lasing part of each electron bunch (black and red vertical dashed lines for the high-energy bunch and low-energy bunch, respectively) and subtracting the values. (c) Distribution of all the delay values for the dataset. Mean error of distribution: 6.8 fs. (d–g) Delay prediction errors for the test set using each of the four models. Experimental points are shown in blue. The perfect correlation lines are included for reference as black dashed lines. Mean error of predictions: 2.07, 1.67, 1.67 and 1.59 fs, respectively. (h) Delay prediction learning curve showing the mean error for the validation set (solid lines), and the training set (dashed lines) for each of the four models as function of the number of samples used for training. ANN: Artificial neural network. SVR: Support vector regressor.