摘要:
The present invention relates to an FTIR spectrometer comprising a single-element detector to analyze a detector light beam emitted by a sample, with a unit to digitize the voltage available at the detector output and with a unit to process the digitized voltage. The single-element detector and the dedicated unit to digitize the detector voltage are located immediately adjacent to each other.
摘要:
In a self-supporting beam-splitter (1), in particular for use in an FTIR-spectrometer for the far-infrared region, with an optical thickness on the order of the interesting wavelength region, the foil beam-splitter (1) consists of an undoped semi-conducter material or carbon which is transparent in the far-infrared, and is preferentially made from thin silicon sheets or diamond foil in the thickness region between 2 .mu.m and 125 .mu.m. In this fashion, an extremely high efficiency for the beam-splitter is achieved, whereby little or no resonant absorption takes place due to the beam-splitter in the interesting wavelength region.
摘要:
A sample holder for placing a sample substance for transmission measurements with optical radiation into a spectrometer, in particular, a FTIR spectrometer which is at least partially made from a material transparent to the optical radiation in a intermeshing wavelength region and which exhibits an index of refraction in excess of 1 is configured as a converging lens with a concave surface (11) and a convex surface (12). To take an absorption spectrum of a powder and/or fluid dissolved or suspended sample substance, the sample substance is brought onto the concave surface (11) of the sample holder before the measurement where it, in consequence of the curvature and in contrast to a flat surface, is concentrated in a substantially smaller surface region. The configuration of the sample holder as a converging lens increases the yield of the radiation penetrating through the sample substance onto the detector of the spectrometer configuration.
摘要:
In an analytic spectrometer (50) having a central computer (9), permanently installed and exchangeable components (5), such as a radiation source, a detector, a beam splitter, a filter, external measurement probes and the like, each of which exhibiting a readable data carrier (7) with encoded data of parameters characterizing the respective component (5), the data media (7) can be written to and contains changeable time dependent data concerning the history and/or the actual properties of the corresponding component (5) for example length of operation, performance deterioration parameters or calibration curves of the component (5). These data can be continuously adjusted by the central computer (9) to the current state of the component (5) so that the data medium (7) connected to the component (5) can immediately supply information concerning the current actual properties of the component (5) when installing the component (5) in another spectrometer.
摘要:
An infrared Fourier transformation spectrometer comprising a non-linear analog-to-digital converter device having at least one amplifier and one sample and hold circuit connected downstream thereof, as well as an an analog-to-digital converter following the latter, wherein an input signal to be converted is to be supplied to one input of the amplifier and the gain of the input signal is a function of the magnitude fo the input signal, and wherein the output signal of the analog-to-digital converter is evaluated giving regard to the respective gain, is characterized by the fact that at least two analog-to-digital converters are provided whose outputs are connected to a first controllable switching arrangement for supplying selectively the output signals of one of the said analog-to-digital converters to another evaulation means and that the input signal is supplied to each of the said analog-to-digital converters amplified by a different amplification factor. This allows to achieve high resolution by simple means.
摘要:
An interferogram is formed as in the prior art by dividing a beam of radiation from the source into two beams and interfering these beams so as to form an interferogram on the detector. A Fourier transform is then made of this interferogram. This transform has a signal spectrum above the cutoff frequency of the detector; and because of non-linearities in the detector and in the electronic signal processing circuitry, this transform also has a spectrum below the cutoff frequency of the detector. In accordance with the invention, two correction factors are calculated from this Fourier transform and these correction factors are then used to calculate a corrected interferogram. The first correction factor is evaluated by determining from the portion of the spectrum below the cutoff frequency a valve for the spectral signal at zero frequency. In addition, the integral of the square of the spectrum signal above the cutoff frequency is determined and the correction factor is found by dividing the signal at zero frequency by the integral of the square of the spectrum above the cutoff. The second correction factor is a function of the first correction factor and the integral of the spectrum signal above cutoff. These two corrections factors are then used in calculating a second order approximation to a corrected interferogram. Finally to produce the corrected Fourier transform, a Fourier transformation is made.
摘要:
As a means for connecting a gas chromatograph and an IR-spectrometer, devices are used which include a cooled carrier which allows to condensate the substances supplied by the gas chromatograph on its surface where they may be examined by spectroscopy. The examination of a new sample makes necessary the evaporation of the substances condensated on this surface before. Up to now, the heating and the cooling of the carrier which was necessary to this end, took a rather long time. Further, the heating of the carrier was limited to a temperature at which not all substances could be completely eliminated from the surface of the carrier. Now, the invention provides for a thermal decoupling of the carrier from the cooling device. Such decoupling allows to heat the carrier to higher tempreatures and to reduce the time needed for performing a measuring cycle, since as a result of the decoupling the cooling device is not heated but the heating is limited to the small mass of the carrier. A removable coupling may be effected by means of a thermally conducting mechanical connection which may be separated, of a gas stream which may be interrupted, or of moving the carrier from a cooling zone to a heating zone.
摘要:
A method for measuring a spectrum of a sample by means of an infrared spectrometer is described, the spectrometer comprising at least one component whose operating behavior is influenced by at least one operating parameter which, in the event of a change, changes the operating behavior of the at least one component and thereby influences the spectrum to be measured, the method comprising detecting the at least one operating parameter at least once during the measurement of the spectrum, reckoning back the operating behavior of the at least one component in a manner dependent on the detected operating parameter to a predetermined reference value of the operating parameter, and further conducting at least one of the following steps: measuring the spectrum on the basis of the predetermined reference value of the operating parameter, correcting the spectrum on the basis of the predetermined reference value of the operating parameter.
摘要:
An optical spectrometer (1) with an interferometer having a means for varying the optical path difference comprising a drive (8), and with a detector (6) for recording optical signals from the interferometer and converting them into electrical analog signals, wherein an analog-to-digital converter (ADC) (9) is connected to the detector (6) digitizing the electrical analog signals in a time-equidistant manner, is characterized in that the data acquisition electronics (17) are supplied by a switched power supply (14), the clock of which is derived from the same reference oscillator (16) as the clock of the signal digitization by the ADC (9). In contrast to known spectrometers with spatially equidistant sampling of the detector signal, the design of the spectrometer according to the invention is considerably cheaper and more compact with respect to its voltage supply elements. Galvanic separation of the data acquisition electronics and the electronic control unit of the linear drive is no longer required.
摘要:
The invention concerns an optical or infrared Fourier spectrometer with a plurality of entrances and exits for the coupling on of external sources or samples. The entrances can also be used as exits and vice versa.