RESUMO
High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders of magnitude higher than at other existing x-ray sources. In order to fully exploit the opportunities offered by these femtosecond light pulses in time-resolved experiments, an unprecedented synchronization accuracy is required. In this Letter, we distributed the pulse train of a mode-locked fiber laser with femtosecond stability to different locations in the linear accelerator of the soft x-ray FEL FLASH. A novel electro-optic detection scheme was applied to measure the electron bunch arrival time with an as yet unrivaled precision of 6 fs (rms). With two beam-based feedback systems we succeeded in stabilizing both the arrival time and the electron bunch compression process within two magnetic chicanes, yielding a significant reduction of the FEL pulse energy jitter.
RESUMO
In this study, we investigated the feasibility of copper ore analysis on a running belt conveyor by measuring the delayed positron annihilation quanta based on the beta-decay of 62Cu, which was previously activated by a D-T, 14â¯MeV neutron generator. We constructed a model of a belt conveyor that measured 10â¯m in length to test this method. Our measurements demonstrated the feasibility of the method but practical constraints imposed by user demands and the industrial environment would make the design impractical and cost inefficient.