Abstract: A smart device “plug-in” radiation module(s) and/or methods are described wherein the bulk of non-sensor radiation circuitry is off-loaded to the smart device. By attaching the radiation module to the smart device via a power/communication port (for example, the smart device's headphone/microphone jack) robust attachment can be achieved as well as uniformity of attachment across different smart devices. A very small radiation module form factor is obtainable, not to mention a very significant cost reduction, allowing widespread adoption of radiation detectors as well as radiation geo-mapping. Power for the radiation module can be obtained from the smart device's headphone plug, utilizing the audio out (speaker) signal's power. Similarly, input to the smart device can be facilitated via the audio in (microphone) signal. Further, output of the radiation module can be visualized on the smart device, as well as control functions.

Abstract: A tumor treatment apparatus may include an array of collimated CZT detectors configured to intersect a known coordinate and measure gamma radiation activity, for example at 511 keV. A radiation delivery system may be configured to direct radiation through the known coordinate on the basis of the gamma radiation activity. A translatable and rotatable table may be configured to support a tumor host, wherein the tumor is positionable relative to the known coordinate on the basis of the gamma radiation activity emitted by the tumor and measured by the array of collimated CZT detectors. Radiation from the radiation delivery system may be delivered to the tumor at the known coordinate, and may be delivered in an intra-operative surgical environment.

Abstract: A method and system for facilitating the identification and/or authentication of objects, and to a method and system for the marking of objects with an identity and/or as of authentic origin, and a set of objects marked to facilitate subsequent identification and/or authentication are described. The marking comprises incorporating into an object or part thereof or onto a tag mechanically engaged therewith a marker material exhibiting a characteristic radiation interaction response to incident high-energy ionizing radiation from a test source that is known to vary spectroscopically across the spectrum of the source. The presence or otherwise of the marker material may be determined by subsequent interrogation of an object with a suitable radiation source and detector to infer whether an object is of marked identity or origin.

Abstract: A multi-modality imaging system for imaging of an object under study, e.g., a whole body or parts of the body of animals such as humans, other primates, swine, dogs, or rodents, that includes a magnetic resonance imaging apparatus and a cadmium zinc telluride (CZT)-family semiconductor, single-photon imaging apparatus within a magnetic field produced by the magnetic resonance imaging apparatus such that sequential or simultaneous imaging can be done with the two modalities using the same support bed of the object under study in the same, uninterrupted imaging session.

Abstract: Radiations detectors with angled walls and methods of fabrication are provided. One radiation detector module includes a plurality of sensor tiles configured to detect radiation. The plurality of sensor tiles have (i) top and bottom edges defining top and bottom surfaces of the plurality of sensor tiles, (ii) sidewall edges defining sides of the plurality of sensor tiles, and (iii) corners defined by the top and bottom edges and the sidewall edges. The radiation detector module also has at least one beveled surface having an oblique angle, wherein the beveled surface includes beveling of at least one of top or bottom edges, the side wall edges, or the corners.

Abstract: A gamma ray detector includes a gamma ray detecting rod elongated along a longitudinal axis, wherein gamma ray detection is enhanced along the longitudinal axis, and a gamma ray shield encapsulating the rod, the shield having an aperture at an end of the detecting rod along the longitudinal axis to admit gamma rays substantially parallel to the longitudinal axis of the elongated detecting rod, wherein gamma ray detection is enhanced along the longitudinal axis and aperture to substantially collimate the sensitivity of the gamma ray detector along the combined aperture and longitudinal axis of the detecting rod.

Abstract: A probe for detecting K-alpha photon emissions. A housing has an aperture at an end. A detector crystal is situated within the housing adjacent to the housing aperture. An energy conversion device is situated within the housing between the detector crystal and the aperture. The energy conversion device is made from a predetermined material configured to convert energy directed through the housing aperture from a source of primary photon emission radiation to a corresponding secondary K-alpha emission within a predetermined emission energy acceptance window. A power supply is coupled to the detector crystal and is configured to establish a polarized electrical field between the anode and the cathode of the detector crystal. The detector crystal receives the K-alpha emission and generates an electrical signal representative of the amount of target emissions received through the housing aperture.

Abstract: A stacked crystal array includes a plurality of crystal slices and a plurality of interconnects. The interconnects have electrically conductive, spaced-apart and generally parallel elements joined by electrically conductive spacers extending generally orthogonally therebetween, the spacers being rotationally offset from each other by a predetermined angle. The array further includes a plurality of electrical insulators and an electrically insulative housing having a plurality of slots. The crystal slices, insulators and interconnects are arranged in the housing to form an assembly wherein the crystal slices are coupled together in a parallel electrical circuit. The assembly provides photon absorption comparable to a monolithic crystal having a thickness generally equivalent to the sum of the thicknesses of the crystal slices, but at a lower bias voltage.

Abstract: A radiation detector includes a semiconductor crystal having a first surface and a second surface opposite to the first surface, a first electrode electrically coupled with the first surface of the semiconductor crystal to allow current to flow between the first electrode and the crystal, and an insulating layer on the first surface and between the semiconductor crystal and the first electrode so as to create a partially transmissive electrical barrier between the first electrode and the crystal. The insulating layer has a thickness ranging from about 50 nanometers to about 500 nanometers.

Abstract: A radiation-sensitive detector includes a first substrate 202 with first and second opposing sides. The first side detects incident radiation, and the first substrate 202 produces a signal indicative of the detected radiation. At least one electrical contact 204 is located on the first substrate 202. An electrically conductive material 214 is coupled to the at least one electrical contact 204. The electrically conductive material 214 has a melting point in a range of about seventy-two (72) degrees Celsius to about ninety-five (95) degrees Celsius.

Abstract: A stacked crystal array includes a plurality of crystal slices and a plurality of interconnects. The interconnects have electrically conductive, spaced-apart and generally parallel elements joined by electrically conductive spacers extending generally orthogonally therebetween, the spacers being rotationally offset from each other by a predetermined angle. The array further includes a plurality of electrical insulators and an electrically insulative housing having a plurality of slots. The crystal slices, insulators and interconnects are arranged in the housing to form an assembly wherein the crystal slices are coupled together in a parallel electrical circuit. The assembly provides photon absorption comparable to a monolithic crystal having a thickness generally equivalent to the sum of the thicknesses of the crystal slices, but at a lower bias voltage.

Abstract: In one embodiment, a system comprises a semiconductor gamma detector material and a hole blocking layer adjacent the gamma detector material, the hole blocking layer resisting passage of holes therethrough. In another embodiment, a system comprises a semiconductor gamma detector material, and an electron blocking layer adjacent the gamma detector material, the electron blocking layer resisting passage of electrons therethrough, wherein the electron blocking layer comprises undoped HgCdTe. In another embodiment, a method comprises forming a hole blocking layer adjacent a semiconductor gamma detector material, the hole blocking layer resisting passage of holes therethrough. Additional systems and methods are also presented.

Abstract: An X-ray detector includes a photoconductor, a first diffusion barrier film on a first surface of the photoconductor, at least one pixel electrode on the first diffusion barrier film, a signal transmitting unit to process an electrical signal output from the at least one pixel electrode, and a common electrode on a second surface of the photoconductor opposite to the first surface of the photoconductor.

Abstract: The invention relates to a neutron detector for detection of neutrons in fields with significant ?- or ?-radiation, comprising a neutron sensitive scintillator crystal, providing a neutron capture signal being larger than the capture signal of 3 MeV ?-radiation, a semiconductor based photo detector being optically coupled to the scintillator crystal, where the scintillator crystal and the semiconductor based photo detector are selected so that the total charge collection time for scintillator signals in the semiconductor based photo detector is larger than the total charge collection time for signals generated by direct detection of ionizing radiation in the semiconductor based photo detector, the neutron detector further comprising a device for sampling the detector signals, a digital signal processing device, means which distinguish direct signals from the semiconductor based photo detector, caused by ?- or ?-radiation and being at least partially absorbed in the semiconductor based photo detector, from lig

Abstract: A ?-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive ?-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a ?-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the ?-radiation. Subsequently, it is determined whether a coincidence exists between the ?-particles and ?-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the ?-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

Abstract: A highly scalable platform for radiation measurement data collection with high precision time stamping and time measurements between the elements in the detection array uses IEEE 1588 with or without Synchronous Ethernet (timing over Ethernet) to synchronize the measurements. At a minimum, the system includes at least two radiation detector units, an IEEE 1588 and SyncE enabled Ethernet switch, and a computer for processing. The addition of timing over Ethernet and power over Ethernet (PoE) allows a radiation measurement system to operate with a single Ethernet cable, simplifying deployment of detectors using standardized technology with a multitude of configuration possibilities. This eliminates the need for an additional hardware for the timing measurements which simplifies the detection system, reduces the cost of the deployment, reduces the power consumption of the detection system and reduces the overall size of the system.

Abstract: A drive controller varies a bias voltage applied from a bias supply to a conversion layer based on the presence or absence of binning, that is, for a case of carrying out binning where switching elements are driven on the basis of a plurality of rows at a time by a gate drive circuit, and for a case of carrying out no binning where the switching elements are driven on a row-by-row basis by the gate drive circuit. Therefore, in the case of a fluoroscopic mode for acquiring images with binning, a lowering of a dynamic range can be suppressed. In the case of a radiographic mode with no binning, spatial resolution can be made high. That is, a high dynamic range and high spatial resolution can be optimized according to modes of operation.

Abstract: The invention provides methods and apparatus for detecting radiation including x-ray, gamma ray, and particle radiation for nuclear medicine, radiographic imaging, material composition analysis, high energy physics, container inspection, mine detection and astronomy. The invention provides detection systems employing one or more detector modules comprising edge-on scintillator detectors with sub-aperture resolution (SAR) capability employed, e.g., in nuclear medicine, such as radiation therapy portal imaging, nuclear remediation, mine detection, container inspection, and high energy physics and astronomy. The invention also provides edge-on imaging probe detectors for use in nuclear medicine, such as radiation therapy portal imaging, or for use in nuclear remediation, mine detection, container inspection, and high energy physics and astronomy.

Abstract: A scanning bone densitometer includes an x-ray source to produce x-rays and an x-ray detector receiving x-rays emitted from the x-ray source. The x-ray detector includes a cadmium tellurium (CdTe) semiconductor. The scanning bone densitometer also includes a controller moving the x-ray source and the x-ray detector along a transverse scanning path to acquire a plurality of scan images of an object of interest.

Abstract: A system in one embodiment includes an array of radiation detectors; and an array of imagers positioned behind the array of detectors relative to an expected trajectory of incoming radiation. A method in another embodiment includes detecting incoming radiation with an array of radiation detectors; detecting the incoming radiation with an array of imagers positioned behind the array of detectors relative to a trajectory of the incoming radiation; and performing at least one of Compton imaging using at least the imagers and coded aperture imaging using at least the imagers. A method in yet another embodiment includes detecting incoming radiation with an array of imagers positioned behind an array of detectors relative to a trajectory of the incoming radiation; and performing Compton imaging using at least the imagers.

Abstract: The disclosure is directed at a radiation detector comprising a substrate layer of detector material; a set of readout electronics deposited and integrated on one side of the substrate layer; and a contact layer deposited on a side of the substrate layer opposite the set of readout electronics.

Abstract: An electronic assembly is provided. The assembly comprises a substrate having a plurality of conductive contacts disposed on a surface of the substrate. The substrate comprises a dielectric material. The assembly comprises a detector having a plurality of conductive contacts disposed on a surface of the detector which is adjacent to the surface of the substrate. At least one compliant interconnect is disposed between the substrate and the detector. The conductive contacts of the substrate and the conductive contacts of the detector are in electrical communication with the compliant interconnect via a conductive epoxy. The compliant interconnect comprises a polymer core having an electrically conductive outer surface. In certain embodiments, the assembly comprises an interposer. In certain embodiments, an under-fill is disposed between the surface of the substrate and the surface of the detector.

Abstract: The invention provides methods and apparatus for detecting radiation including x-ray, gamma ray, and particle radiation for nuclear medicine, radiographic imaging, material composition analysis, high energy physics, container inspection, mine detection and astronomy. The invention provides detection systems employing one or more detector modules comprising edge-on scintillator detectors with sub-aperture resolution (SAR) capability employed, e.g., in nuclear medicine, such as radiation therapy portal imaging, nuclear remediation, mine detection, container inspection, and high energy physics and astronomy. The invention also provides edge-on imaging probe detectors for use in nuclear medicine, such as radiation therapy portal imaging, or for use in nuclear remediation, mine detection, container inspection, and high energy physics and astronomy.

Abstract: The invention provides methods and apparatus for detecting radiation including x-ray, gamma ray, and particle radiation for nuclear medicine, radiographic imaging, material composition analysis, high energy physics, container inspection, mine detection and astronomy. The invention provides detection systems employing one or more detector modules comprising edge-on scintillator detectors with sub-aperture resolution (SAR) capability employed, e.g., in nuclear medicine, such as radiation therapy portal imaging, nuclear remediation, mine detection, container inspection, and high energy physics and astronomy. The invention also provides edge-on imaging probe detectors for use in nuclear medicine, such as radiation therapy portal imaging, or for use in nuclear remediation, mine detection, container inspection, and high energy physics and astronomy.

Abstract: The present invention provides a two-terminal infrared detector capable of detecting a plurality of bands, such as three bands, over the visible and short-wave infrared bands. Detection of three colors enables one to construct composite imagery that provide significantly added contract in comparison to typical grayscale images. In some variations, the device includes multiple absorber and barrier layers that consist of distinct engineered semiconductor alloys which are closely lattice matched to InP.

Abstract: A detector module is disclosed including a plurality of directly converting detector submodules, each with a back contact, and a scattered radiation collimator spanning the detector submodules. For contacting the back contacts, a contacting unit is provided in at least one embodiment and designed so that a contact connection is established between the contacting unit and the counter-electrodes by way of assembly-related proximity of the scattered radiation collimator and the counter-electrodes.

Abstract: A device includes (a) radiation detector including a semiconductor substrate having opposing front and rear surfaces, a cathode electrode located on the front surface of said semiconductor substrate, and a plurality of anode electrodes on the rear surface of said semiconductor substrate, (b) a printed circuit board, and (c) an electrically conductive polymeric film disposed between circuit board and the anode electrodes. The polymeric film contains electrically conductive wires. The film bonds and electrically connects the printed circuit board and anode electrodes.

Abstract: A method of detecting ionizing radiation is provided.

Abstract: A radiation imaging device (10). The radiation image device (10) comprises a subject radiation station (12) producing photon emissions (14), and at least one semiconductor crystal detector (16) arranged in an edge-on orientation with respect to the emitted photons (14) to directly receive the emitted photons (14) and produce a signal. The semiconductor crystal detector (16) comprises at least one anode and at least one cathode that produces the signal in response to the emitted photons (14).

Abstract: The present invention relates to a novel hybrid anode configuration for a radiation detector that effectively reduces the edge effect of surface defects on the internal electric field in compound semiconductor detectors by focusing the internal electric field of the detector and redirecting drifting carriers away from the side surfaces of the semiconductor toward the collection electrode(s).

Abstract: The invention relates to converter element (100) for a radiation detector, particularly for a Spectral CT scanner. The converter element (100) comprises at least two conversion cells (131) that are at least partially separated from each other by intermediate separation walls (135) which affect the spreading of electrical signals generated by incident radiation (X). The conversion cells (131) may particularly consist of a crystal of CdTe and/or CdZnTe. Said crystal is preferably grown by e.g. vapor deposition between preformed separation walls.

Abstract: A radiological imaging apparatus using a semiconductor radiation detector to make it possible to reduce a radiation measurement off time that may result from an attempt to avoid polarization, the radiological imaging apparatus comprising a capacitor that applies a voltage to a semiconductor radiation detector that detects a radiation from a subject, first current regulated means for conducting a charge current to the capacitor, and second current regulated means for conducting a discharge current from the capacitor, or comprising a capacitor that applies a voltage to the semiconductor radiation detector, a first resistor that conducts a charge current to and a discharge current from the capacitor, and a second resistor connected in parallel with the first resistor to subject the capacitor to charging and discharging.

Abstract: A substrate for forming a semiconductor layer includes a plurality of linear convexes or grooves on a surface of the substrate by crystal growth. The plurality of linear convexes or grooves are formed along a direction of a cleavage plane of the semiconductor layer.

Abstract: Tomography by emission of positrons (pet) system dedicated to examinations of human body parts such as the breast, axilla, head, neck, liver, heart, lungs, prostate region and other body extremities which is composed of at least two detecting plates (detector heads) with dimensions that are optimized for the breast, axilla region, brain and prostrate region or other extremities; motorized mechanical means to allow the movement of the plates under manual or computer control, making it possible to collect data in several orientations as needed for tomographic image reconstruction; an electronics system composed by a front-end electronics system, located physically on the detector heads, and a trigger and data acquisition system located off-detector in an electronic crate; a data acquisition and control software; and an image reconstruction and analysis software that allows reconstructing, visualizing and analyzing the data produced during the examination.

Abstract: A scanning bone densitometer includes an x-ray source to produce x-rays and an x-ray detector receiving x-rays emitted from the x-ray source. The x-ray detector includes a cadmium tellurium (CdTe) semiconductor. The scanning bone densitometer also includes a controller moving the x-ray source and the x-ray detector along a transverse scanning path to acquire a plurality of scan images of an object of interest.

Abstract: A radiation detector includes a semiconductor crystal having a first surface and a second surface opposite to the first surface, a first electrode electrically coupled with the first surface of the semiconductor crystal to allow current to flow between the first electrode and the crystal, and an insulating layer on the first surface and between the semiconductor crystal and the first electrode so as to create a partially transmissive electrical barrier between the first electrode and the crystal. The insulating layer has a thickness ranging from about 50 nanometers to about 500 nanometers.

Abstract: A radiation detection apparatus includes an optical detector disposed on a substrate and having a plurality of photoelectric conversion elements which convert light into an electrical signal, and a scintillator layer disposed on the optical detector and having a columnar crystal structure which converts radiation into light, wherein the concentration of an activator of the scintillator layer is higher at the radiation-incident side opposite the optical detector and is lower at the optical detector side. The scintillator panel includes the substrate and the scintillator layer disposed on the substrate, wherein the concentration of the activator of the scintillator layer is higher at the radiation-incident side and is lower at the light-emission side.

Abstract: Methods and systems for determining a location of a photon event for an imaging system including a plurality of 3-D detectors. For one of the photons in the photon pair, an interaction in a first 3-D detector is detected. For the other of the photons in the photon pair, at least two interactions in a second 3-D detector are detected. A cone-surface projector function is produced based on the at least two interaction locations in the second 3-D detector. A projector function is produced based on the produced cone-surface projector function, the detected interaction in the first 3-D detector, and the at least two detected interactions in the second 3-D detector.

Abstract: A stacked crystal array includes a plurality of crystal slices and a plurality of interconnects. The interconnects have electrically conductive, spaced-apart and generally parallel elements joined by electrically conductive spacers extending generally orthogonally therebetween, the spacers being rotationally offset from each other by a predetermined angle. The array further includes a plurality of electrical insulators and an electrically insulative housing having a plurality of slots. The crystal slices, insulators and interconnects are arranged in the housing to form an assembly wherein the crystal slices are coupled together in a parallel electrical circuit. The assembly provides photon absorption comparable to a monolithic crystal having a thickness generally equivalent to the sum of the thicknesses of the crystal slices, but at a lower bias voltage.

Abstract: A radiation-sensitive detector includes a first substrate 202 with first and second opposing sides. The first side detects incident radiation, and the first substrate 202 produces a signal indicative of the detected radiation. At least one electrical contact 204 is located on the first substrate 202. An electrically conductive material 214 is coupled to the at least one electrical contact 204. The electrically conductive material 214 has a melting point in a range of about seventy-two (72) degrees Celsius to about ninety-five (95) degrees Celsius.

Abstract: A radiation detector includes a semiconductor element capable of detecting a radiation, a substrate on which the semiconductor element is mounted, and a flexible substrate including a connection pattern connected to an element electrode on an opposite side to the substrate of the semiconductor element. The semiconductor element is disposed on one surface of the substrate, and the flexible substrate is disposed on the opposite side to the substrate of the semiconductor element.

Abstract: The present invention provides an orofacial radiation detection device for detection of radionuclide contamination from inhalation. The device includes a face mask including a support frame and an adjustable head strap connected to the support frame. Mounted on the frame are radiation detectors in selected locations so that when being worn by a person, the detectors are located in close proximity to the orofacial region of the person including their nose and mouth. The device includes an electronic controller connected to the detectors for controlling operation of the radiation detectors. The device includes a microcomputer mounted on the support frame and electrically connected to the electronic controller for processing signals from the detectors for allowing input from an operator, performing data analysis and detection algorithms, and outputting results.

Abstract: The present invention provides a semiconductor radioactive ray detector having the excellent energy resolution or time precision, a radioactive detection module, and a nuclear medicine diagnosis apparatus. The semiconductor radioactive ray detector has a structure in which plate-like elements made of cadmium telluride and conductive members are alternately laminated and the plate-like element made of cadmium telluride and the conductive member are adhered to each other with a conductive adhesive agent, and the Young's modulus of the conductive adhesive agent is in the range from 350 MPa to 1000 MPa, while the conductive members are made from a material with the linear expansion coefficient of the conductive members in the range from 5×10?6/° C. to 7×10?6/° C.

Abstract: A semiconductor substrate is composed of a SiC crystal. A metal film having a desired area and serving as an incident surface onto which X-rays are made incident is formed on one surface of the semiconductor substrate. An electrode having the shape of a circle is formed at the central portion of the other surface of the semiconductor substrate. A ring-shaped electrode is formed in a portion near the circumference of the semiconductor substrate so as to surround the electrode. A predetermined direct voltage is applied to the metal film and the ring-shaped electrode. A voltage of a ground level is applied to the electrode. X-rays (?-rays) that are made incident onto the metal film cause the generation of electron-hole pairs in the semiconductor substrate. The generated electrons are collected at the electrode and drawn as electric signals from an output terminal.

Abstract: A CdTe or CdZnTe radiation imaging detector and high voltage bias part for applying a high voltage to the continuous electrode to ensure stable performance of the detector. The high voltage bias part includes conductors of >30 um diameter and preferably selected from a group of materials that do not oxidize easily or oxidize less than aluminium.

Abstract: An embodiment of the invention includes a radiation detecting pixel array. The radiation detecting pixel array includes a substrate, a plurality of radiation detecting pixels arranged in a grid pattern on the substrate, a signal routing array embedded within the substrate in operative communication with the plurality of radiation detecting pixels, and at least two symmetrical communication channels arranged on each of two sides of the grid pattern. The signal routing array is formed of communication channels configured to provide operative communication between any of the plurality of radiation detecting pixels and each of the at least two symmetrical communication channels.

Abstract: A specimen inspection system includes a photon source for outputting photons along a transmission path and a conveyor for translating a specimen completely through the transmission path. A radiation detector is positioned offset with respect to the transmission path for detecting photons that are scattered from the transmission path in response to interaction with the specimen passing therethrough. A controller determines from the detected scattered photons that a first material is present in the specimen.

Abstract: A method is provided for fabricating contacts on semiconductor substrates by direct lithography that results in durable adhesion of the electrodes, increased interpixel resistance and the electrodes which act as a blocking contact, thereby providing for improved energy resolution in a resultant radiation detector.

Abstract: An X-ray detector includes: a semiconductor substrate to generate charged particles by an irradiation of an X-ray; a plurality of pixel electrodes arranged in matrix on an X-ray incident surface of the semiconductor substrate and applied with a first electric potential to detect the charged particles; and a platy electrode provided on a surface opposite to the X-ray incident surface of the semiconductor substrate and applied with a second electric potential different from the first electric potential.

Abstract: At least one embodiment of the invention relates to an X-ray radiation detector, in particular for use in a CT system. In at least one embodiment, the X-ray radiation detector includes a semiconductor material used for detection, at least two ohmic contacts between the semiconductor material and a contact material, the semiconductor material and contact material each having a specific excitation energy of the charge carriers, with the excitation energy of the contact material corresponding to the excitation energy of the semiconductor material. At least one embodiment of the invention furthermore relates to a CT system in which an X-ray radiation detector is used, the X-ray radiation detector advantageously having at least two ideal ohmic contacts according to at least one embodiment of the invention.