Echelle polychromator

In an Echelle polychromator, having a basic Echelle polychromator unit that has a basic entrance slit arrangement of a basic main slit and a basic transverse slit that is disposed transversely to the basic main slit, basic collimator optics, a basic prism, an Echelle grating, basic camera optics, and a detector arrangement, the improvement comprising:

• (a) a dispersive and polychromatic illuminating supplemental device for producing a radiation spectrum having a dispersion-induced geometric width, said supplemental device being connected in series before the basic Echelle polychromator, the supplemental device comprising a supplemental entrance slit arrangement comprised of a supplemental main slit and a supplemental transverse slit that is disposed transversely to the basic main slit, supplemental collimator optics, a supplemental prism having a transverse dispersion, and supplemental camera optics;
• (b) said basic and said supplemental entrance slit arrangements each comprise a main slit for limiting in the direction of the grating dispersion the bundle of radiation emitted by a source, and a transverse slit for limiting the bundle of emitted radiation in the direction of the dispersion of the basic prism,
• (c) the entirety of the wavelength range to be processed by the basic polychromator is imaged substantially completely with minimal aberration on the basic transverse slit as a radiation spectrum of the supplemental device;
• (d) the radiation dispersion of the supplemental device runs in the direction of the transverse dispersion of the basic prism;
• (e) the dispersion-induced geometric width of the spectrum of the radiation from the supplemental device for the entirety of the wavelength region to be processed by the basic polychromator, is less than the width of the basic transverse slit;
• and
• (f) parts of the bundle of radiation of the spectrum of the supplemental device are blocked out by the basic transverse slit.