Abstract: The invention relates to a percussion instrument having at least two tone bars, each with an upper and lower side and at least one resonance box with at least one resonance body, wherein the resonance body consists of a neck and a resonance chamber.

Abstract: The invention relates to a percussion instrument having at least two tone bars, each with an upper and lower side and at least one resonance box with at least one resonance body, wherein the resonance body consists of a neck and a resonance chamber.

Abstract: A photoacoustic multipass cell includes a light source, an acoustic resonator and a reflecting arrangement configured in a concentrating manner for reflecting light into the acoustic resonator. Additionally, the light source is arranged at least partially within the reflecting arrangement.

Abstract: A photoacoustic detection device includes a cylindrical acoustic resonator having an arrangement for guiding light essentially perpendicular to a cylinder axis in such a manner that a second azimuthal resonance of cylinder oscillation is excitable by absorption of the light.

Abstract: A photoacoustic detector for providing a measurement, includes a first light source and a second light source each configured to provide light of a same intensity while retaining a same spectral distribution. Additionally, the photoacoustic detector includes a first beam path allocated to the first light source and at least one second beam path allocated to the second light source, wherein a different absorption of light occurs in the first path and the second beam path in at least one selected wavelength range. Further, the photoacoustic detector includes a photoacoustic measuring cell; and a mechanism for alternately guiding light from the first beam path and from the second beam path into the photoacoustic measuring cell.

Abstract: A gas detector with a selectively adsorbing surface (3) and an acoustic measuring cell (5) is presented. The detector is characterized in that the selectively adsorbing surface (3) and the acoustic measuring cell (5) can be arranged with respect to one another such that gases desorbed by means of thermal desorption from the adsorbing surface (3) reach the acoustic measuring cell (5) and there trigger a pressure wave that can be measured by one or more acoustic pick-ups (13, 14), in particular microphones, which are arranged in the acoustic measuring cell (5). Furthermore, a corresponding method is provided. The detector is particularly suitable for measuring contaminants in interior spaces and ventilation systems.

Abstract: A method for measuring a photoacoustic signal using light sources that emit light at different wavelengths, wherein the method comprises electing a scanning frequency with which signals are recorded, determining a modulation frequency for each light source by dividing the scanning frequency by an integer division value that is different for each light source, exciting a photoacoustic signal in a photoacoustic measuring cell using the light sources and the modulation frequency, measuring, with a sound pressure sensor, a produced sound pressure, digitizing a signal of the sound pressure sensor, determining a signal component assignable to a respective light source by evaluating a sequence of digitized measured values, and filtering out measured value components that occur periodically with a period of a respective modulation frequency.

Abstract: A photoacoustic detector for measuring a concentration of fine dust particles in gas. The detector includes at least one acoustic sensor for detecting an acoustic signal. Additionally, the detector includes a pulsed light source for providing excitation light having a configurable pulse length and a configurable pulse repetition rate, wherein by changing the pulse length and/or the pulse repetition rate, a size distribution of the fine dust particles can be determined.

Abstract: A device is presented for photoacoustic detection, having a cylindrical acoustic resonator (1), in which means (3a-d) are present for guiding the excitation light such that the sound wave that can be excited by absorption of the excitation light is the second azimuthal resonance of the cylinder oscillation.

Abstract: The invention relates to a photoacoustic multipass cell with a light source and means (3) for reflecting light in an acoustic resonator (8), which means are embodied in a concentrating manner, wherein the light source is arranged between the means designed in a concentrating manner. Two spherical mirrors (3) with a common optical axis can be used as a means for reflecting the light. The light source is represented by a fiber (5) guided into the multipass cell or a laser diode.

Abstract: A photoacoustic detector is presented having the following structure: a first and a second light source (1a, b) for providing light of the same intensity while retaining the same spectral distribution; a first beam path allocated to the first light source (1a) and at least one second beam path allocated to the at least one second light source (1b), wherein a different absorption of light can occur in the first and second beam paths in selected wavelength ranges; means (4) for alternately guiding light from the first and from the at least one second beam path into a photoacoustic measuring cell (6), the intensity of the light sources being constant in such a way that the temporal change thereof cannot generate a photoacoustic signal that distorts the measurement.

Abstract: The invention relates to a photoacoustic detector for measuring the concentration of fine dust particles, especially carbon particles in gas, comprising a pulsed light source for providing excitation light, wherein a size distribution of the fine dust particles can be determined by changing the pulse length and/or the pulse repetition rate.

Abstract: The application relates to a method for measuring the photoacoustic signal in a photoacoustic cell (4) with several light sources (5,6,7,8) that emit light at different wavelengths.

Abstract: A gas detector with a selectively adsorbing surface (3) and an acoustic measuring cell (5) is presented. The detector is characterized in that the selectively adsorbing surface (3) and the acoustic measuring cell (5) can be arranged with respect to one another such that gases desorbed by means of thermal desorption from the adsorbing surface (3) reach the acoustic measuring cell (5) and there trigger a pressure wave that can be measured by one or more acoustic pick-ups (13, 14), in particular microphones, which are arranged in the acoustic measuring cell (5). Furthermore, a corresponding method is provided. The detector is particularly suitable for measuring contaminants in interior spaces and ventilation systems.

Abstract: The invention relates to a photoacoustic detector including an acoustically open measuring area which is not completely surrounded by a housing. The detector includes an arrangement for introducing excitation light into the measuring area, such that the excitation light can be absorbed by absorbent materials which are located in the measuring area and which are used to produce acoustic energy. The invention also relates to a detector which includes at least one acoustic sensor and an arrangement is provided in order to concentrate the acoustic energy, in order to reach a local maximum of the acoustic pressure on at least one position. The at least one sensor is arranged in the vicinity of the at least one position, whereon the local maximum of the produced acoustic pressure is present or can be produced. The invention also relates to an associated method.