Multi-resolution electron spectrometer array for future free-electron laser experiments

The design of an angular array electron time-of-flight (eToF) spectrometers is reported, intended for non-invasive spectral, temporal, and polarization characterization single shots high-repetition rate, quasi-continuous, short-wavelength free-electron lasers (FELs) such as the LCLS II at SLAC. This also enables angle-resolved, high-resolution eToF spectroscopy to address a variety scientific questions on ultrafast nonlinear light–matter interactions FELs. presented device specifically designed time-resolved atomic, molecular optical science endstation (TMO) II. In its final version, spectrometer comprises up 20 aligned collect electrons from interaction point, which defined by intersection incoming FEL radiation gaseous target. full composition involves 16 forming circular equiangular in plane normal X-ray propagation four 54.7° angle relative principle linear axis with orientations forward backward direction light propagation. are capable independent minimally chromatic electrostatic lensing retardation, order enable simultaneous angle-resolved photo- Auger–Meitner high energy resolution. They ensure resolution 0.25 eV across window 75 eV, can be individually centered via adjustable retardation cover range kinetic energies relevant soft methods, 0–2 keV. will online spectral-polarimetry measurements, polarization-sensitive attoclock characterizing time–energy structure SASE or seeded pulses, support emerging trends molecular-frame measurements.