Abstract: A method for determining a correcting quantity function kF(x, y) for calibrating an FTIR measurement arrangement with an IR detector. The IR detector includes a plurality of sensor elements, which are each located at a position (x, y), and the method includes: (a) recording interferograms IFGRxy of a reference sample using the sensor elements of the IR detector, (b) calculating spectra Rxy of the reference sample by Fourier transforming the interferograms of the reference sample for at least four sensor elements, (c) calculating correcting quantities kxy by comparing each spectrum Rxy of the reference sample calculated in step b) with a reference data set of the reference sample, and (d) determining the correcting quantity function kF(x, y) using the correcting quantities kxy calculated in step c). This permits frequency shifts that occur in FTIR spectrometers with extensive detectors to be effectively corrected regardless of the position of the sensor element.

Abstract: An IR microscope includes an IR light source/interferometer (1) generating a collimated IR beam (26), an effectively beam-limiting element (8) in a stop plane (27), a sample position (15), a detector (19) having an IR sensor (19a), a detector stop (19b), a first optical device focusing the collimated IR beam onto the sample position, and a second optical device imaging the sample position onto the IR sensor. The effectively beam-limiting element is situated in the collimated IR beam. The first and second optical devices image the detector stop opening into an input beam plane. For the area A1 of the image of the detector stop opening in the input beam plane and the area A2 of the cross section of the collimated IR beam in the input beam plane: 0<A1/A2?1. Thereby, only collimated IR radiation is picked up, while vignetting and stray radiation are avoided.

Abstract: A desorber for a spectrometer, comprising a housing, which has supply lines and discharge lines for a sample carrier gas, together with a closable opening, and an induction unit arranged in the housing, wherein the induction unit comprises a high-permeability and electrically insulating coil carrier, a coil arranged in the coil carrier, a high-permeability sample carrier that can be removed via the closable opening, wherein the sample carrier is designed as an inductive heating element, for purposes of heating a substance to be desorbed, which is applied to the sample carrier, and the coil carrier and the coil are arranged spaced apart from the sample carrier by a gap, such that the magnetic flux, generated by an alternating current flowing in the coil, flows through the sample carrier via the coil carrier and the gap.

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: An interferometer arrangement includes a beam splitter (8), two retroreflectors (15, 16), a drive (24) that moves at least one of the retroreflectors to alter an optical path difference between interferometer arms (13, 14), a converging element (18) for reference light, and a reference light detector (19) with at least three detector areas (19a-19d). First and second pairs of detector areas are aligned in respective first and second directions, wherein the first direction, the second direction and a central propagation direction of the reference light at the reference light detector are linearly independent. At least two actuators (9, 10) alter a lateral shear between two reference light partial beams (11, 12), which are reflected back from the interferometer arms and superimposed at the beam splitter, in at least two degrees of freedom. Control electronics (38) control the actuators depending on signals (Sa-Sc) at the detector areas, thereby minimizing the shear.