Seeded free-electron laser driven by a compact laser plasma accelerator

Free-electron lasers generate high-brilliance coherent radiation at wavelengths spanning from the infrared to the X-ray domains. The recent development of short-wavelength seeded free-electron lasers now allows for unprecedented levels of control on longitudinal coherence[1], opening new scientific avenues as ultra-fast dynamics on complex systems and X-ray nonlinear optics. While those devices rely on state-of-the-art large-scale accelerators, advancements on laser-plasma accelerators, which harness giga-volt-per-centimeter accelerating fields, showcase a promising technology as compact drivers for free-electron lasers. Using such miniaturized accelerators, exponential amplification of a shot-noise type of radiation in a self-amplified spontaneous emission configuration was recently achieved [2]. However, employing this compact approach for the delivery of temporally coherent pulses in a controlled manner remained a major challenge. Here, we present the experimental demonstration of a laser-plasma accelerator driven free-electron laser in a seeded configuration, where control over the radiation wavelength is accomplished. Furthermore, the appearance of interference fringes, resulting from the interaction between the phase-locked emitted radiation and the seed, confirms longitudinal coherence. Building on our scientific achievements, we anticipate a straightforward scaling to extreme-ultraviolet wavelengths, paving the way towards university-scale free-electron lasers, unique tools for a multitude of applications. [1] Meyer, M. FELs of europe: Whitebook on science with free electron lasers 8–19 (2016). [2] Wang, W. et al. Free-electron lasing at 27 nanometres based on a laser wakefield accelerator

Similar 5-year HCC occurrence in Tenofovir- and Entecavir-treated HBV chronic infection in the French AFEF/ANRS CO22 Hepather cohort.

International audienceBackground: Chronic hepatitis B virus (HBV) infection results in a high risk of cirrhosis and its complications, cirrhosis decompensation (DC), hepatocellular carcinoma (HCC), liver transplantation (LT), death or any of these outcomes (composite endpoint [CE]). Nucleos(t)ide analogues (NUCs) such as tenofovir or entecavir are associated with a reduction in these complications.Aim: To compare the impact of tenofovir and entecavir on these outcomes in patients treated for HBV infection and included in the prospective Hepather cohort.Methods: All patients with HBV infection who had received tenofovir or entecavir for more than 6 months at or after entry in the ANRS CO22 cohort were selected. Patients with HDV and HCV co-infection or prior liver event were excluded. Incidence rates of events were compared using inverse probability of treatment weighting (IPW).Results: The cohort included 1800 patients (986 tenofovir and 814 entecavir). Median follow-up was 4.2 years. The incidences of HCC, DC, LT, ACD, LRD and CE were not different between tenofovir- (1.8 (0.9; 3.2), 0.6 (0.2; 1.6), 0.2 (0.0; 0.8), 1.7 (0.8; 3.0), 0.8 (0.2, 1.8) and 4.1 (3.0; 5.4) per 1000 person-years) and entecavir-treated patients (1.6 (0.7; 3.0), 0.7 (0.2; 1.8), 0.2 (0.0; 1.0), 3.0 (1.7, 4.8), 0.5 (0.1; 1.5) and 5.0 (3.3; 7.2)) per 1000 person-years, respectively.Conclusion: The risk of liver-related events or death was not different between tenofovir- and entecavir-treated patients in this large prospective cohort of predominantly non-cirrhotic French patients.Trial registration number: NCT019553458