Fig. 1. Layout of the SXFEL

Fig. 2. Total wakefield in the bypass-line 1 and bypass-line 2. = 0 represents the head of the bunch, and the y-axis represents wakefield in MeV unit

Fig. 3. Wakefield in the copper flat-plate pipe. The = 0 represents the head of the bunch, and the y-axis represents wakefield in MeV unit

Fig. 4. Total wakefield for bypass-line 1, bypass-line 2 and the copper flat-plate pipe. = 0 represents the head of the bunch, and y-axis represents wakefield in MeV unit

Fig. 5. Experimental layout of SXFEL

Fig. 6. (a) Distribution for bunch A, and (b) measured and calculated wakefields in bypass-line 1

Fig. 7. Measured longitudinal phase space in position 1 and position 2. The figure is separated in 500×500 pixels, and x axis stands for bunch length (left is beam head),y stands for the energy (top is higher energy)

Fig. 8. The energy distribution in position 1 and position 3

Fig. 9. (a) Distribution for bunch B and (b) measured and calculated wakefields for all the pipes