Fig. 1. Principle of fiber beam loss monitoring system

Fig. 2. Schematic diagram of data acquisition system for fiber beam loss monitoring

Fig. 3. Schematic diagram of fiber beam loss monitoring system position calibration

Fig. 4. Diagram of beam loss generated by BPM falling YAG target

Fig. 5. Beam loss waveforms generated by YAGs falling on SBP beamline

Fig. 6. Attenuation coefficient of optical fiber fitted by the peak values of beam loss signals generated by falling YAGs(a) 100 m fiber, (b) 180 m fiber

Fig. 7. Effect of attenuation on Cherenkov light spectrum (remaining part of spectrum after propagation through different fiber lengths) (a), cathode radiation sensitivity of the Hamamatsu H10721-01 (b)

Fig. 8. Attenuation coefficient fitted by calculation under different fiber lengths (a) 100-m-long fiber, (b) 180-m-long fiber

Fig. 9. Beam loss signals generated by falling the upstream first YAG(a) Signal generated by the first bunch, (b) Signal generated by the second bunch

Fig. 10. Layout diagram of the SXFEL fiber beam loss monitoring system

Fig. 11. Beam loss signal captured by optical fiber of SBP beamline during the period of beam tuning