Abstract: An electroacoustic transducer 400 is described. The electroacoustic transducer 400 comprises an active element 410. The electroacoustic transducer 400 comprises an acoustic coupling layer 430 arranged to acoustically couple, in use, the active element 410 to a transmission medium. The electroacoustic transducer 400 further comprises a cavity 420 arranged between the active element 410 and the acoustic coupling layer 430 to receive a fluid. In this way, acoustic coupling of the electroacoustic transducer 400 and the transmission medium is improved.

Abstract: The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

Abstract: A method and apparatus for classifying and/or identifying materials by means of their spectral response to gamma radiation. Classification is carried out by irradiating multiple different samples with gamma radiation, detecting a spectral response in the backscatter direction, sorting the spectral response into energy bands and selecting a combination of energy bands to define a relationship that best distinguishes between clusters of spectral responses for different material classes. Two or more of the energy bands may overlap.

Abstract: A radiation backscatter detector assembly comprising: a source array comprising source components for irradiating a shared sample location, at least two source components of the array generating radiation in different respective source energy bands; a detector array comprising detector elements for detecting backscattered radiation detection events from different respective spatial portions of the shared sample location, the detector elements each generating a pulse output in response to each radiation detection event it detects; and an energy meter for measuring the energies of the pulse outputs by different respective detector elements.

Abstract: A releasable clamp 10 for holding an article 1000 or parts thereof is describe. The clamp 10 comprises: a set of jaws, including a first jaw 100A and a second jaw 100B, arrangeable to hold the article 1000 therebetween; a set of spacers, including a first spacer 200A, arrangeable to space apart respective jaws of the set of jaws; and a set of retaining members, including a first retaining member 300A, arrangeable to space together respective jaws of the set of jaws; wherein respective jaws of the set of jaws comprise a first region 110 for contacting the article 1000, an optional second region 120 defining a portion of a first part 410 of a coupling member 400, a third region 130 for contacting a respective spacer of the set of spacers and a fourth region 140 for contacting a respective retaining member of the set of retaining members.

Abstract: The scintillation detector assembly 10 comprises a first scintillation detector 11A of a set SSD of scintillation detectors 11, comprising a first scintillator 12A of a set SS of scintillators 12 and a first light sensor 13A of a set SLS of respective light sensors 13 optically coupled thereto, arranged to detect electromagnetic radiation and output a first signal; a first radiation source 14A of a set SRS of radiation sources 14, configured to emit first gamma radiation G1 of a first set SG of gamma radiation G, having a first reference energy RE1 of a set SRE of respective first reference energies RE; and a controller 15 configured to control a gain of the first scintillation detector 11A based, at least in part, on the first gamma radiation, having the first reference energy, detected by the first scintillation detector 11A.

Abstract: According to a first aspect of the present invention, there is provided a method for transmitting and/or receiving an optical signal through a fluid, the method comprising: using a pressure wave to cause a change in refractive index in the fluid, the change in refractive index causing a waveguide to be formed; and transmitting and/or receiving the optical signal through the waveguide.

Abstract: A radiation backscatter detector assembly comprising: a source array comprising source components (110, 115) for irradiating a shared sample location, at least two source components of the array generating radiation in different respective source energy bands; a detector array comprising detector elements (500, 220) for detecting backscattered radiation detection events from different respective spatial portions of the shared sample location, the detector elements each generating a pulse output in response to each radiation detection event it detects; and an energy meter (325) for measuring the energies of the pulse outputs by different respective detector elements.

Abstract: According to the present invention, there is provided an electroacoustic transducer, comprising: a first electrode; a second electrode; a piezoelectric material at least partially sandwiched between the first electrode and the second electrode; and an optical aperture extending through the electroacoustic transducer, to allow for optical communication to take place through the electroacoustic transducer.

Abstract: According to a first aspect of the present invention, there is provided a method for transmitting and/or receiving an optical signal through a fluid, the method comprising: using a pressure wave to cause a change in refractive index in the fluid, the change in refractive index causing a waveguide to be formed; and transmitting and/or receiving the optical signal through the waveguide.

Abstract: There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.

Abstract: An electroacoustic transducer 400 is described. The electroacoustic transducer 400 comprises an active element 410. The electroacoustic transducer 400 comprises an acoustic coupling layer 430 arranged to acoustically couple, in use, the active element 410 to a transmission medium. The electroacoustic transducer 400 further comprises a cavity 420 arranged between the active element 410 and the acoustic coupling layer 430 to receive a fluid. In this way, acoustic coupling of the electroacoustic transducer 400 and the transmission medium is improved.

Abstract: An electroacoustic transducer array 110 is described. The electroacoustic transducer array 110 comprises a first electroacoustic transducer 40A comprising a first active element 41A and a second electroacoustic transducer 40B comprising a second active element 41B. The electroacoustic transducer array 110 comprises an acoustic coupling layer 43 arranged to acoustically couple, in use, the first active element 41A and the second active element 41B to a transmission medium. The electroacoustic transducer array 110 comprises a first cavity 42A arranged between the first active element 41A and the acoustic coupling layer 43 to receive a first fluid; and/or a second cavity 42B arranged between the second active element 41B and the acoustic coupling layer 43 to receive a second fluid. In this way, acoustic coupling of the electroacoustic transducer array 110 and the transmission medium is improved.

Abstract: According to the present invention, there is provided an electroacoustic transducer, comprising: a first electrode; a second electrode; a piezoelectric material at least partially sandwiched between the first electrode and the second electrode; and an optical aperture extending through the electroacoustic transducer, to allow for optical communication to take place through the electroacoustic transducer.

Abstract: According to the present invention, there is provided an electroacoustic transducer, comprising: a first electrode; a second electrode; a piezoelectric material at least partially sandwiched between the first electrode and the second electrode; and a flexible electrical connector in electrical connection with the first or second electrode at discrete points around a periphery of that electrode, the discrete points being distributed about a substantial portion of that periphery.

Abstract: According to the present invention, there is provided an electroacoustic transducer, comprising: a first electrode; a second electrode; a piezoelectric material at least partially sandwiched between the first electrode and the second electrode; and a flexible electrical connector in electrical connection with the first or second electrode at discrete points around a periphery of that electrode, the discrete points being distributed about a substantial portion of that periphery.

Abstract: There is disclosed an acoustic transducer for communications within an operational bandwidth, the transducer comprising: A signal generator for generating a signal at a centre-frequency within the operational bandwidth; A piezoelectric element having a dielectric constant that varies with temperature; A driving electrode at the surface of the piezoelectric element; A matching network, having a natural frequency at a given temperature, and operable to transfer the signal from the signal generator to the piezoelectric element whilst mitigating electrical loss, the matching network being connected to the driving electrode; Wherein the matching network comprises a temperature compensating capacitor connected in parallel with the piezoelectric element, the temperature compensating capacitor being for counteracting temperature-induced changes to the dielectric constant of the piezoelectric element such that the electrical natural frequency of the transducer is substantially constant over a range of temperatures.

Abstract: There is disclosed herein a transducer for acoustic communications through a series arrangement of fluid and solid media, the transducer comprising: —a signal processor configured to implement a communications scheme at and around a center frequency of at least 1 MHz; a piezoelectric element for activation in accord with the communications scheme; an electrode electrically connected to the signal processor, and being attached to the piezoelectric element; and a substrate, having the piezoelectric element mounted thereon, wherein an aspect of the electrode at the piezoelectric element is approximately equal to the acoustic wavelength of an acoustic wave in the substrate at the center frequency. There is further disclosed a remote monitoring device employing at least one of the transducers described, in concert with a further transducer. Still further, there is disclosed a method of communicating using the transducer described herein.

Abstract: In an arrangement for transmitting power or data through a solid rigid substrate without penetrating the substrate, acoustic transducer components are mounted on the substrate by means of strain isolator elements which are welded or otherwise bonded to the substrate and providing an attachment surface to which the attachment interface of the acoustic transducer may be attached. The strain isolator element is of the same or similar acoustic impedance as the rigid substrate and may indeed be formed of the same material. Various geometries of strain isolator are disclosed, including a plain spacer block, and one comprising a stalk attached to the solid rigid substrate and topped by a disc in a ‘mushroom’ configuration.

Abstract: In an arrangement for transmitting power or data through a solid rigid substrate without penetrating the substrate, acoustic transducer components are mounted on the substrate by means of strain isolator elements which are welded or otherwise bonded to the substrate and providing an attachment surface to which the attachment interface of the acoustic transducer may be attached. The strain isolator element is of the same or similar acoustic impedance as the rigid substrate and may indeed be formed of the same material. Various geometries of strain isolator are disclosed, including a plain spacer block, and one comprising a stalk attached to the solid rigid substrate and topped by a disc in a ‘mushroom’ configuration.