Abstract: In an embodiment an X-ray source includes an electron source configured to emit electrons, an acceleration set-up configured to accelerate the emitted electrons and a transmission window downwards of the acceleration set-up, wherein the transmission window is configured to let through X-rays generated by the accelerated electrons, wherein the transmission window is located either in a straight extension of a line-of-flight of the accelerated electrons or off the line-of-flight and past the acceleration set-up, wherein the transmission window comprises a carbon carrier, and wherein the carbon carrier comprises sp2-hybridized carbon.

Abstract: In at least one embodiment an X-ray source includes an electron source configured to emit electrons, an acceleration set-up configured to accelerate the emitted electrons and a transmission window downwards of the acceleration set-up, the transmission window configured to let through X-rays generated by the accelerated electrons, wherein the transmission window incudes a carbon carrier, and wherein the carbon carrier includes sp2-hybridized carbon.

Abstract: An optical spectrometer comprises at least two coupling apertures with different mode field diameters, a means for dispersing the light beams exiting each of the coupling apertures along a dispersion axis and at least two decoupling apertures on which the dispersed light beams are imaged and whose mode field diameters each correspond to the mode field diameters of the associated coupling apertures. Due the enlarged mode field diameter, a larger spectral fraction of dispersed light beams, i.e., light of a larger spectral bandwidth, can be coupled into the decoupling aperture than into the decoupling aperture.

Abstract: An optical spectrometer comprises at least two coupling apertures with different mode field diameters, a means for dispersing the light beams exiting each of the coupling apertures along a dispersion axis and at least two decoupling apertures on which the dispersed light beams are imaged and whose mode field diameters each correspond to the mode field diameters of the associated coupling apertures. Due the enlarged mode field diameter, a larger spectral fraction of dispersed light beams, i.e., light of a larger spectral bandwidth, can be coupled into the decoupling aperture than into the decoupling aperture.