Soft X-ray spectroscopy of clusters, surfaces and interfaces

UNIEXP

Research

FEL Physics and Instrumentation Development

FLASH - Split and Delay Line ·

FLASH - Split and Delay Line

The free-electron laser in Hamburg (FLASH) at DESY is a source for intense, coherent, ultra-short and tuneable soft x-ray radiation. It has opened the door to study multi-photon, nonlinear processes as well as ultra-fast dynamics of atoms and in highly correlated systems. To further enhance the possbibilities of FLASH, a XUV split-and-delay line (Mach-Zehnder type autocorrelator) has been developed [1] and in the framework of the GrK 1355 "Physik mit neuartigen kohärenten Strahlungsquellen" been implemented and characterized in the plane grating monochromator beamline PG2. This device is able to split the ultrashort XUV pulses and delay them up to 5.1ps with a hundred attosecond reproducability. It is now possbile to study ultrafast XUV induced dynamics in a site-selective way.
This device can be used to study the temporal coherence properties of FLASH at various wavelengths for different machine setups. Furthermore, the monochromator in the PG2 beamline allows to study temporal coherence properties energy resolved at the expense of lengthening the pulses.

Measures results of the longitudinal coherence time.

Interference fringes arise when the splitted beam are overlapped again in time and space on a detector.

CAD of the XUV split and delay unit integrated in the PG2 beamline at FLASH.

[1] Rev. Sci. Instrum. 81, 043107 (2010)