Abstract: Ion mobility spectrometers and methods for determining the ion mobility of a sample gas in dry air as drift gas are disclosed. The ion mobility spectrometers comprise a drift chamber, a reaction chamber, a dielectric barrier discharge ionisation source, a control unit, and a DBDI source, a pressure sensor, and a temperature sensor arranged in the chamber. A light source irradiates the DBDI source with light in a wavelength range from about 240 nm to about 480 nm. The control unit is designed to set an ignition voltage of the DBDI source and to control the light source depending on a determined pressure value and a determined temperature value. The methods control and utilize the control unit for operating the ion mobility spectrometer.

Abstract: Ion mobility spectrometers and methods for determining an ion mobility spectrum of a sample are provided. The ion mobility spectrometers comprise a drift chamber and a cylindrical reaction chamber, wherein the drift chamber is designed to transport ions from a switching grid to an ion detector against an axial drift gas flow. The reaction chamber has a sample gas inlet adjacent to the switching grid for introducing a sample gas, a gas outlet opposite the switching grid for discharging drift gas and sample gas, and a local ionisation source arranged at the gas outlet. The sample gas inlet comprises gas inlets arranged oppositely on an inner circumference of the reaction chamber. The methods operate the ion mobility spectrometers to determine an ion mobility spectrum of a sample.

Abstract: An infrared microscope includes a radiation source, a sample plane, an objective lens, a path length modulator and a detector. The radiation source emits temporally coherent infrared radiation that propagates along an optical path of the microscope during operation. A sample is disposed in the sample plane. The detector detects the infrared radiation after the radiation interacts with the sample. The objective lens forms an image of the sample plane on the detector. The path length modulator continuously varies the optical path length of the optical path between the sample plane and the detector. The path length modulator can be a wedge or a diffusing screen that rotates during operation, a phase modulator that rotates during operation and that has regions with different indices of refraction, a tilting element that tilts about an axis during operation, or a diffuser mirror that reflects the infrared radiation and that rotates during operation.

Abstract: A lens arrangement for an optical unit operating in a predetermined spectral range, includes at least two lenses (11-14, 114) of material, which transmits in the spectral range, and a common casing (15), in which the lenses are arranged sequentially. The lenses are at least substantially aligned radially, axially and angularly inclined relative to a common optical axis. Adjacent lenses in the sequence are mounted to allow relative movement therebetween. Abutment faces (2) of the lenses rest against one another. An elastic tensioner (21) pretensions the sequence of lenses in the axial direction. Only one of the lenses (11) in the sequence is axially aligned by way of the common casing. Only a portion of the lenses (11, 114) in the sequence are radially aligned by the common casing; the remaining lenses are aligned with respect to one another by the abutment faces of the respectively adjacent lenses.

Abstract: A method for measuring and determining a THz spectrum of a sample (17) having an improved spectral resolution. Two laser beams (1a, 2a) are superimposed, such that two parts (11, 12) of a superimposed laser radiation are generated, which have a beat frequency in the THz range. The first part (11) is introduced into an emitter (13) for generating a THz radiation (14), which passes through the sample. The characteristic transmission radiation (18) thus obtained is forwarded to a detector (15), which is activated by the second part (12) of the superimposed laser radiation. By repetition with different beat frequencies, a measurement signal I(f) of the form I(f)=A(f)·cos [?(f)] is obtained for the sample. An auxiliary signal ?(f) shifted by 90° is determined from the measurement signal I(f), with ?(f)=A(f)·cos [?(f)±90°]. The THz spectrum S(f) of the sample is determined by the auxiliary signal ?(f), with S(f)=|z(f)|=|I(f)+i?(f)|.

Abstract: An IR microscope (1) is constituted such that, in an optical viewing mode in a beam path of visible light (VIS-R, VIS-T), a first intermediate focus (ZW1) is imaged onto a flat detector surface (15a) of a camera. The IR microscope (1) is constituted such that, in the beam path of the visible light (VIS-R, VIS-T), the first intermediate focus (ZW1) is imaged onto a second intermediate focus (ZW2), and, in the second intermediate focus (ZW2), a Mangin mirror (11) is disposed that corrects a field curvature of the Cassegrain objective (4). The invention provides an IR microscope in which the field curvature generated by the Cassegrain objective is corrected in a simple manner in the optical viewing mode when detection is performed using a flat detector and without restricting the spectral range of the IR microscope.

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber for a sample gas to be analyzed and an inlet and an outlet which are connected thereto. A traversing optical path for a measuring beam is formed in the inner chamber. The measuring cell is tubular, the inlet and the outlet are arranged at opposite ends, and the inner chamber of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.

Abstract: A method for the acquisition (AU) of a spectrally resolved, two-dimensional image by means of Fourier transform (FT) spectroscopy or Fourier transform infrared (FTIR) spectroscopy, is characterized in that, during multiple passes (D1-D4) of an optical path difference (OG) between two partial rays (14a, 14b) over an identical range (IB), different subsets of detector elements (22) of an array detector (5) are read out and the signals of the read-out detector elements (22) of the multiple passes (D1-D4) are Fourier transformed and combined to form the spectrally resolved image. A method is thereby provided for the acquisition of two-dimensional, spectrally resolved images, in which the influence of vibrations on the measurement is reduced, and which is less affected by the movement of objects to the resolved spectrally.

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber (23) for a sample gas to be analyzed and an inlet (21) and an outlet (22) which are connected thereto. A traversing optical path for a measuring beam (14) is formed in the inner chamber (23). The measuring cell is tubular, the inlet (21) and the outlet (22) are arranged at opposite ends, and the inner chamber (23) of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.

Abstract: An ATR objective (1) for an IR microscope has a Cassegrain objective (2), an ATR crystal (7), a holding bar (8) to one end of which on the side of the sample, the ATR crystal (7) is mounted, a holding element (10), thin struts (9) which rigidly connect the holding bar (8) to the holding element (10) and intersect an optical path of the ATR objective (1) entering or exiting the Cassegrain objective (2) in such a fashion that they shade less than 10% of the beam cross-section of the optical path, and a motor drive (12) for axial movement of the holding element (10) relative to the sample position (3). The automated ATR objective thereby enables simple adjustment of operating modes and different contact pressures of the ATR crystal with respect to a sample (19).

Abstract: A measuring cell for a gas analysis spectrometer has an inner chamber (23) for a sample gas to be analyzed and an inlet (21) and an outlet (22) which are connected thereto. A traversing optical path for a measuring beam (14) is formed in the inner chamber (23). The measuring cell is tubular, the inlet (21) and the outlet (22) are arranged at opposite ends, and the inner chamber (23) of the measuring cell has a cross-sectional shape that is monotonic over the length of the tube and which has an oval-shape at the start, which disappears toward the end. That special shape results in fast gas exchange and thus high dynamics, even with larger measuring cells, which have high sensitivity due to the long optical paths thereof. Two characteristics which until now appeared to be conflicting are thereby combined.

Abstract: An IR microscope (1) is constituted such that, in an optical viewing mode in a beam path of visible light (VIS-R, VIS-T), a first intermediate focus (ZW1) is imaged onto a flat detector surface (15a) of a camera. The IR microscope (1) is constituted such that, in the beam path of the visible light (VIS-R, VIS-T), the first intermediate focus (ZW1) is imaged onto a second intermediate focus (ZW2), and, in the second intermediate focus (ZW2), a Mangin mirror (11) is disposed that corrects a field curvature of the Cassegrain objective (4). The invention provides an IR microscope in which the field curvature generated by the Cassegrain objective is corrected in a simple manner in the optical viewing mode when detection is performed using a flat detector and without restricting the spectral range of the IR microscope.

Abstract: An infrared (IR) spectrometer (20) for IR spectroscopic investigation of a test sample (1) in a first wavenumber range WB1, comprising a sample container (1a) for the test sample (1), wherein the sample container (1a) is transparent to IR radiation in the first wavenumber range WB1, and wherein the IR spectrometer (20) comprises a measuring device for determining the temperature of the test sample (1), is characterized in that the measuring device comprises an IR sensor (2) which measures, without contact, the intensity of the IR radiation emitted by the sample container (1a), and the sample container (1a) is opaque to IR radiation in the second wavenumber range WB2. A simple and reliable measurement of the temperature of a test sample in an IR spectrometer is thereby enabled.

Abstract: A method for the acquisition (AU) of a spectrally resolved, two-dimensional image by means of Fourier transform (=FT) spectroscopy or Fourier transform infrared (=FTIR) spectroscopy, is characterized in that, during multiple passes (D1-D4) of an optical path difference (OG) between two partial rays (14a, 14b) over an identical range (IB), different subsets of detector elements (22) of an array detector (5) are read out and the signals of the read-out detector elements (22) of the multiple passes (D1-D4) are Fourier transformed and combined to form the spectrally resolved image. A method is thereby provided for the acquisition of two-dimensional, spectrally resolved images, in which the influence of vibrations on the measurement is reduced, and which is less affected by the movement of objects to the resolved spectrally.

Abstract: An infrared (IR) spectrometer (20) for IR spectroscopic investigation of a test sample (1) in a first wavenumber range WB1, comprising a sample container (1a) for the test sample (1), wherein the sample container (1a) is transparent to IR radiation in the first wavenumber range WB1, and wherein the IR spectrometer (20) comprises a measuring device for determining the temperature of the test sample (1), is characterized in that the measuring device comprises an IR sensor (2) which measures, without contact, the intensity of the IR radiation emitted by the sample container (1a), and the sample container (1a) is opaque to IR radiation in the second wavenumber range WB2. A simple and reliable measurement of the temperature of a test sample in an IR spectrometer is thereby enabled.

Abstract: ATR (attenuated total reflection) objective (1) for an IR (infrared) microscope, comprising a Cassegrain objective (2) which focuses on a sample position (3) and the two mirrors (2a,2b) of which each have a central bore (5a, 5b), an ATR crystal (7), a holding bar (8) which is guided through the two central bores (5a, 5b) and to one end of which on the side of the sample, the ATR crystal (7) is mounted, a holding element (10) which is disposed in the area or beyond the side of the Cassegrain objective (2) facing away from the sample, thin struts (9) which rigidly connect the holding bar (8) to the holding element (10) and intersect an optical path of the ATR objective (1) entering or exiting the Cassegrain objective (2) in such a fashion that they shade less than 10% of the beam cross-section of the optical path, and a motor drive (12) for axial movement of the holding element (10) relative to the sample position (3).

Abstract: An apparatus for the analysis of a sample by means of an infrared (IR) spectroscopy, comprising a vessel (1) rotating during operation for holding the sample, a measuring head (2, 2?) connected with the vessel, a spectrometer (8) which is supplied with IR radiation reflected by the sample, and at least one first optical fiber element (4a) for transmitting the IR radiation reflected by the sample, is characterized in that the spectrometer (8) is stationary and a first rotary feed through (7, 7?, 7a, 7a?) is provided for coupling the reflected IR radiation from the first optical fiber element (4a) into a second optical fiber element (4b), in which the first optical fiber element (4a) is connected with the rotating part of the first rotary feed through (7, 7?, 7a, 7a?) and the spectrometer (8) is connected with the stationary part of the first rotary feed through (7, 7?, 7a, 7a?) via the second optical fiber element (4b).

Abstract: A method is provided for correcting at least one portion of a spectrum, in particular a Raman spectrum, by eliminating a baseline which is due to a perturbing spectrum, in particular due to a fluorescence spectrum, superimposed on the spectrum, wherein i) a convex envelope of the spectrum is determined, at least in the portion of the spectrum which is to be corrected, and ii) the convex part of the envelope lying below the spectrum is subtracted from the spectrum in the portion to be corrected. Before step i), iii) a convex function f is added to the spectrum in the portion to be corrected.

Abstract: A spectrometer system (1) comprising an IR (infrared) spectrometer (2) and an IR microscope (3), wherein a sample (42) and a first detector (21; 31) are provided in the IR microscope (3), wherein the IR microscope (3) is designed such that during measurement, the sample (42) is imaged on the first detector (21; 31) via an intermediate focus (44), is characterized in that at least one second detector (24, 25; 33) is provided whose detector surface (26, 27; 34) extends parallel to the detector surface (22; 32) of the first detector (21; 31), the detector surface (26, 27; 34) of the at least one second detector (24, 25; 33) is at least 5 times larger than the detector surface (22; 32) of the first detector (21; 31), and the first (21; 31) and the at least one second detector (24, 25; 33) are disposed directly next to each other, wherein the detector surface (26, 27; 34) of the at least one second detector (24, 25; 33) largely surrounds the detector surface (22; 32) of the first detector (21, 31), and the first d

Abstract: A method is provided for correcting at least one portion of a spectrum, in particular a Raman spectrum, by eliminating a baseline which is due to a perturbing spectrum, in particular due to a fluorescence spectrum, superimposed on the spectrum, wherein i) a convex envelope of the spectrum is determined, at least in the portion of the spectrum which is to be corrected, and ii) the convex part of the envelope lying below the spectrum is subtracted from the spectrum in the portion to be corrected. Before step i), iii) a convex function f is added to the spectrum in the portion to be corrected.