Tanikawa, T.; Hage, A.; Kuhlmann, M.; Gonschior, J.; Grunewald, S.; Plönjes, E.; Düsterer, S.; Brenner, G.; Dziarzhytski, S.; Braune, M.; Brachmanski, M.; Yin, Z.; Siewert, F.; Dzelainis, T.; Dromey, B.; Prandolini, M.J.; Tavella, F.; Zepf, M.; Faatz, B.: First observation of SASE radiation using the compact wide-spectral-range XUV spectrometer at FLASH2. Nuclear Instruments & Methods in Physics Research A 830 (2016), p. 170-175
10.1016/j.nima.2016.05.088
Abstract:
The Free-electron LASer in Hamburg(FLASH)hasbeenextendedwithanewundulatorlineFLASH2in 2014. Acompactgrazing-incidentwide-spectral-rangespectrometerbasedonspherical-variable-line- spacing (SVLS)gratingsintheextremeultraviolet(XUV)regionwasconstructedtooptimizeandcharacterize thefree-electronlaser (FEL) performanceatFLASH2. Thespectrometerisequippedwiththree different concaveSVLSgratingscoveringaspectralrangefrom1to62nmtoanalyzethespectral characteristicsoftheXUVradiation.Wavelengthcalibrationandevaluationofthespectralresolution wereperformedattheplanegratingmonochromatorbeamlinePG2atFLASH1beforetheinstallationat FLASH2, andcomparedwithanalyticalsimulations.The first lightusingself-amplified spontaneous emission fromFLASH2wasobservedbythespectrometerduringasimultaneousoperationofboth undulator lines—FLASH1 andFLASH2.Inaddition,thespectralresolutionofthespectrometerwas evaluatedbycomparingthemeasuredspectrumfromFLASH2withFELsimulations.