Transmission NEXAFS

nm liquid film Absorption

End station for time-resolved and steady-state soft x-ray absorption spectroscopy (XAS/NEXAFS/XANES/EXAFS) in transmission on liquid samples. The liquid sample is continiously refreshed in a flatjet system. The transmitted intensity of synchrotron radiation for ground state NEXAFS is measured with a gallium arsenide (GaAs) photodiode. Here, the average diode current is recorded as a measure of transmitted intensity. For static measurements the full filling pattern of BESSY II is used. For time resolved measurement a MHz laser is incoupled to the end station. For time resolved studies an avalanche photo diode (APD) is used to separate the "single bunch" in the hybrid filling pattern of BESSY II. 

For details see: M. Fondell, S. Eckert, R. M. Jay, C. Weniger, W. Quevedo, J. Niskanen, B. Kennedy, F. Sorgenfrei, D. Shick, E. Giangrisostomi, R. Ovsyannikov, K. Adamzyk, N. Huse, P. Wernet, R. Mitzner, A. Föhlisch, "Time-resolved soft X-ray absorption spectroscopy in transmission mode onliquids at MHz repetition rates", Structural dynamicsRev. Sci. Instrum. 4, 054902 (2017).

(a) Schematic top view of the experimental layout for static and time resolved NEXAFS measurements of liquid samples. (b) Thickness variation across a water flatjet based on the transmitted intensity

Methods