Abstract:
The invention relates to a spectrometer arrangement (10) having a spectrometer for producing a spectrum of radiation from a radiation source on a detector (34), comprising an imaging, optical Littrow arrangement (18, 20) for imaging the radiation entering the spectrometer arrangement (16) in an image plane, a first dispersion arrangement (28, 30) for the spectral decomposition of a first wavelength range of the radiation entering the spectrometer arrangement, a second dispersion arrangement (58, 60) for the spectral decomposition of a second wavelength range of the radiation entering the spectrometer arrangement, and a common detector (34) arranged in the image plane of the imaging optics, characterized in that the imaging optical arrangement (18, 20) comprises an element (20) that can be moved between two positions (20, 50), wherein the radiation entering the spectrometer arrangement in the first position is guided via the first dispersion arrangement and in the second position via the second dispersion arrangement.
Abstract:
An echelle spectrometer arrangement (10) with internal order separation contains an echelle grating (34) and a dispersing element (38) for order separation so that a two-dimensional spectrum having a plurality of separate orders (56) can be generated, an imaging optical system (18, 22, 28, 46), a flat-panel detector (16), and predispersion means (20) for predispersing the radiation into the direction of traverse dispersion of the dispersion element (38). The arrangement is characterized in that the predispersion means (20) comprise a predispersion element which is arranged along the optical path behind the inlet spacing (12) inside the spectrometer arrangement. The imaging optical system is designed in such a manner that the predispersed radiation can be imaged onto an additional image plane (24) which does not have any boundaries in the predispersion direction and which is arranged along the optical path between the predispersion element (20) and the echelle grating (34). Optical means (20, 68) in the area of the predispersed spectrum are arranged to influence the spatial and/or the spectral beam density distribution on the detector (16).
Abstract:
The invention relates to a spectrometer arrangement (10) having a spectrometer for producing a spectrum of radiation from a radiation source on a detector (34), comprising an imaging, optical Littrow arrangement (18, 20) for imaging the radiation entering the spectrometer arrangement (16) in an image plane, a first dispersion arrangement (28, 30) for the spectral decomposition of a first wavelength range of the radiation entering the spectrometer arrangement, a second dispersion arrangement (58, 60) for the spectral decomposition of a second wavelength range of the radiation entering the spectrometer arrangement, and a common detector (34) arranged in the image plane of the imaging optics, characterized in that the imaging optical arrangement (18, 20) comprises an element (20) that can be moved between two positions (20, 50), wherein the radiation entering the spectrometer arrangement in the first position is guided via the first dispersion arrangement and in the second position via the second dispersion arrangement.
Abstract:
Ein Verfahren zur Untergrundbestimmung und- Korrektur von breitbandigem Untergrund, ist gekennzeichnet durch die Schritte: Glätten der aufgenommenen Spektralkurve; Bestimmen aller Werte der ursprünglichen Kurve, deren Wert über dem Wert der geglätteten Kurve liegt, und Reduzierung dieser Werte auf den Wert der geglätteten Kurve; wenigstens zweifaches Wiederholen der Schritte und Subtraktion der auf diese Weise erhaltenen Untergrundkurve von der ursprünglichen Kurve. Das Glätten der Kurve kann mittels Moving Average erfolgen. Die Breite des Moving Average kann das Doppelte einer durchschnittlichen Linienbreite einer Referenzlinie betragen.
Abstract:
Ein Verfahren zur Wellenlängenkalibrierung von Echellespektren, bei denen sich die Wellenlängen auf eine Mehrzahl von Ordnungen verteilen, ist gekennzeichnet durch die Schritte: Aufnehmen eines linienreichen Referenzspektrums mit bekannten Wellenlängen für eine Vielzahl der Linien, Bestimmen der Lage einer Vielzahl von Peaks des Referenzspektrums in dem aufgenommenen Spektrum, Auswählen von wenigstens zwei ersten Linien mit bekannter Ordnung, Lage und Wellenlänge, Bestimmen einer Wellenlängenskala für die Ordnung, in welcher die bekannten Linien liegen, durch eine Fitfunktion λ m (x), Bestimmen einer vorläufigen Wellenlängenskala λ m±1 (x) für wenigstens eine benachbarte Ordnung m±1 durch Addition/Subtraktion einer Wellenlängendifferenz Δλ FSR , die einem freien Spektralbereich entspricht nach λ m±1 (x) = λ m (x) ± Δλ FSR , mit Δλ FSR =λ m (x)/m, Bestimmen der Wellenlängen von Linien in dieser benachbarten Ordnung m±1 mittels der vorläufigen Wellenlängenskala λ m±1 (x), Ersetzen der vorläufigen Wellenlänge von wenigstens zwei Linien durch die nach Schritt (a) vorgegebene Referenzwellenlänge dieser Linien, und Wiederholen der Schritte (d) bis (g) für wenigstens eine weitere benachbarte Ordnung.
Abstract:
A method and apparatus for the spectrochemical analysis of a sample in which a solid state array detector (82) is used to detect radiation (62) of spectrochemical interest. The invention involves the use of a shutter (72) adjacent the entrance aperture (70) of a polychromator (74-80) to expose the detector (82) to the radiation (62) for varying lengths of time whereby for short duration exposure times charge accumulation in elements (i.e. pixels) of the detector (82) due to high intensity components of the radiation is limited and for longer exposure times charge accumulation in elements (pixels) of the detector (82) due to feeble intesity components of radiation (62) is increased. This ensures that each reading of the detector (82) includes at least one exposure in which the amount of charge accumulated at each wavelength of interest is neither too little or too great. The problems of feeble radiation components not being accurately measurable and of high intensity radiation components exceeding the charge carrying capacity of elements (pixels) of the detector (82) are thereby able to be avoided. An attenuator (90) may be placed between the radiation source (60) and the detector (82) to permit longer exposure times to be used for very high intensity radiation.
Abstract:
An improved spectrometer comprises a slit in light blocking plate, an echelle grating, and a detector array. The slit is shaped and oriented to align an image of a light beam projected through the slit, onto the echelle grating and onto the detector in a desired orientation and shape relative to the detector array. Precise adjustment of the shape and orientation of the slit is dependent on the orientation of the detector with respect to the dispersion direction of the echelle grating. The spectrometer provides high detector resolution with reduced read-out time.