This disclosure presents a process to determine characteristics of a subterranean formation proximate a borehole. Borehole material can be typically pumped from the borehole, though borehole material can be used within the borehole as well. Extracted material of interest can be collected from the borehole material and prepared for analyzation. Typically, the preparation can utilize various processes, for example, separation, filtering, moisture removal, pressure control, cleaning, and other preparation processes. The prepared extracted material can be placed in a photoacoustic device where measurements can be taken, such as a photoacoustic imager or a photoacoustic spectroscopy device. A photoacoustic analyzer can generate results utilizing the measurements, where the results of the extracted material can include one or more of fracture parameters, fracture plane parameters, permeability parameters, porosity parameters, and composition parameters. The results can be communicated to other systems and processes to be used as inputs.

The invention relates to a device (1) and a corresponding method for mid-infrared microscopy and/or analysis, the device (1) comprising at least one radiation unit (10) configured to generate radiation (11) of time-varying intensity, the radiation (11) comprising one or more wavelengths in the mid-infrared spectral range, at least one refractive and/or reflective optical unit (12) which is configured to focus and/or direct the radiation (11) to at least one region or point of interest (20) located on and/or with-in an object (2), at least one detection unit (18) configured to detect ultrasound waves (17) emitted by the object (2) at the at least one region or point of interest (20) in response to an interaction of the radiation (11) with the object (2) and to generate according detection signals, and an evaluation unit (25) configured to derive infor-mation regarding at least one property of the object (2) from the detection signals and/or to generate a spatial and/or spatio-temporal distribution of the detection sig-nals or of information derived from the detection signals obtained for the at least one region or point of interest (20) located on and/or within the object (2).

A photoacoustic sensor comprises an emitter for emitting electromagnetic radiation at a first wavelength and electromagnetic radiation at a second wavelength, wherein the first wavelength is for photoacoustically detecting particulate matter in a measurement cavity and the second wavelength is for photoacoustically detecting the particulate matter and at least one target gas in the measurement cavity. The photoacoustic sensor further comprises an acoustic transducer for transducing a first acoustic signal into a first sensor signal depending on an interaction of the electromagnetic radiation at the first wavelength and the particulate matter, and for transducing a second acoustic signal into a second sensor signal depending on an interaction of the electromagnetic radiation at the second wavelength with the particulate matter and the at least one target gas.

A detector cell for a photoacoustic gas sensor comprises a first layer structure, a second layer structure arranged at the first layer structure and comprising a membrane structure, and a third layer structure arranged at the second layer structure. The first layer structure and the third layer structure hermetically enclose a cavity, wherein the membrane structure is arranged in the cavity.

A photoacoustic apparatus may include: a ring transducer configured to measure a photoacoustic signal generated from an object, and including a hollow space that is provided as a travel path of light and ultrasonic waves; a mirror part disposed along a light path of the light transmitted from the ring transducer, and configured to reflect the light transmitted from the ring transducer, and the ultrasonic waves generated from the object, and to adjust magnification of the mirror part according to a number of apertures of the photoacoustic apparatus; and a fluid tank including a transparent film that allows the photoacoustic signal to pass through the fluid tank, and accommodating a fluid, the ring transducer, and the mirror part inside the fluid tank.

A photoacoustic detector unit comprises a housing having an opening, and also a photoacoustic transducer designed to convert optical radiation into at least one from a pressure signal or a heat signal. The photoacoustic transducer covers the opening of the housing, such that the photoacoustic transducer and the housing form an acoustically tight cavity. A pressure pick-up is arranged in the acoustically tight cavity.

A system and method for detecting gas sensing employs a waveguide for both electromagnetic and acoustic radiation. Electromagnetic radiation is intensity-modulated and introduced into a waveguide. The waveguide is perforated to admit a gas that absorbs energy at the wavelength of the electromagnetic radiation. An acoustic wave is produced in the waveguide with a frequency equal to the modulation frequency of the electromagnetic radiation. The acoustic wave is received by an acoustic sensor and the presence of the gas is determined in accordance with the received acoustic wave.

Methods include treating a portion of a sample composition to be tested for presence of an analyte by depleting or blocking the target analyte. The treated composition may be used to equilibrate an acoustic wave sensor prior to exposing the sensor to the untreated sample composition for analysis. By using the treated sample composition, in which the analyte is depleted or blocked, to equilibrate the sensor, the sensor may be equilibrated with a composition having a similar viscosity and non-specific binding characteristics to the untreated sample composition, which should result in improved accuracy when analyzing the analyte in the untreated sample composition.

The invention relates, in a first aspect, to a photoacoustic spectroscope for analyzing gas, comprising an infrared emitter (3), which can be modulated, an analysis volume (1), which can be filled with gas, and a sound pressure detector. The sound pressure detector comprises a structure (5) capable of vibrating, an actuator and a measurement unit, wherein the actuator is configured to actively excite vibration of the structure (5) capable of vibrating and the measurement unit can measure the vibration properties of the structure (5) capable of vibrating, which measurement depends on the formation of the sound pressure waves.

In an additional aspect, the invention relates to a method for analyzing gas, comprising the provision of a photoacoustic spectroscope for analyzing gas, irradiating the gas with infrared radiation, modulated by a modulation frequency, to generate sound pressure waves, exciting the structure (5) capable of vibrating at an excitation frequency, measuring the vibration properties of the structure (5) capable of vibrating, which measurement depends on the sound pressure, and determining the sound pressure of the gas based on the measured vibration properties.

A system for measuring gas concentration includes a package having a cavity and a port, a photoacoustic gas sensor device within the package, and a Micro Electro Mechanical System (“MEMS”) valve separate from the photoacoustic gas sensor device placed over the port of the package and to allow ambient gas diffusion into the cavity in a first mode of operation, and to prevent ambient gas diffusion into the cavity and to acoustically isolate the cavity in a second mode of operation.