Abstract: A sample inspection apparatus includes a source of electromagnetic radiation, a beam former for producing a plurality of coaxial and substantially conical shells of radiation, a detection surface and a set of conical shell slot collimators. Each conical shell has a different opening angle. The detection surface is arranged to receive diffracted radiation after incidence of one or more of the conical shells upon the sample to be inspected. The set of conical shell slot collimators is provided at or close to the detection surface which each stare at different annular regions of different corresponding conical shells.

Abstract: There is presented an apparatus for identifying a sample. Such an apparatus may be used to detect unwanted items as part of a security screening system. The apparatus includes a platform for receiving the sample, at least one electromagnetic radiation emitter, a plurality of detectors and a calculator. The electromagnetic radiation emitter is adapted to provide a plurality of conical shells of radiation. Each conical shell has a characteristic propagation axis associated with it. The detectors are arranged to detect radiation diffracted by the sample upon incidence of one or more conical shells of radiation. Each detector is located on the characteristic propagation axis associated with a corresponding conical shell. The calculator is adapted to calculate a parameter of the sample based on the detected diffracted radiation. The parameter includes a lattice spacing of the sample.

Abstract: A system for inspecting a moving person comprises an x-ray source, disposed in a fixed position with respect to the moving person, to generate one or more scanning x-ray beams. Each of the one or more x-ray beams being obliquely incident on either a front of the moving person, a rear of the moving person, or both. The system further comprises one or more backscatter detectors arranged to detect radiation scattered from the moving person, and to produce a detection signal therefrom. The system further comprises a processor and a memory with computer code instructions stored thereon. The memory is operatively coupled to the processor such that, when executed by the processor, the computer code instructions cause the system to produce a backscatter image based on the detection signal. When two or more x-ray beams are implemented, the two or more x-ray beams are temporarily interleaved to prevent crosstalk.

Abstract: Method, apparatus, system, and computer program product for inspecting a joining feature on an object. A portable housing with an x-ray system is moved along the joining feature on the object. The x-ray system is controlled to direct an x-ray beam through an opening in the portable housing to scan an area of the object containing the joining feature as the portable housing moves along the joining feature on the object. Sensor data generated from a backscatter detected by a sensor system is received. The backscatter is generated in response to the x-ray beam encountering the area of the object including the joining feature. A determination is made as to whether an inconsistency is present in the area of the object including the joining feature using the sensor data.

Abstract: A support unit and a collimator are relatively rotated about the axis of rotation by a rotation driving device. The collimator has a blocking region that blocks X-rays and a transmission region that allows X-rays to pass therethrough. The transmission region has a vertex positioned on the axis of rotation, and the circumferential length of the transmission region increases proportionally as it advances outward from the vertex. A sample supported by the support unit is irradiated with X-rays by an X-ray source through the transmission region of the collimator, and the fluorescent X-rays from the sample are detected by the detector. The analysis of a composition of a sample is performed based on the fluorescent X-rays detected by the detector.

Abstract: A linear accelerator target apparatus includes a target material to produce radiation upon being struck by electrons accelerated by a linear accelerator and a target holder assembly to which the target material is attached. The target holder assembly includes a cooling channel disposed around a perimeter of the target material. The target holder assembly is configured to be detachably coupled to a housing of the linear accelerator. The target apparatus further includes a protective window coupled to the target holder assembly over the target material.

Abstract: The present invention consists of a system and a method for a rapid, complete and nonintrusive inspection of vessels without their physical control. The nonintrusive control method, in accordance with the invention, consists in the relative movement of a vessel, through two scanning frames, in a manner synchronized with the triggering of two penetrating radiation generators and the transmission of the signals generated by the detector matrix towards the subsystem for the acquisition, processing and display of data in order to form and display radiographic images from at least two different perspectives of the scanned vessel. The scanning system, according to the invention, consists of a support-type mechanical structure, a control center, two scanning frames, two penetrating radiation sources, a vessel towing subsystem, a subsystem for vessel stabilization and a subsystem for the acquisition, processing and display of data.

Abstract: An image processor applies computation processing to a plurality of CT images formed by irradiation of radiation of a plurality of energy levels to acquire monochromatic CT images. The image processor acquires a first energy level CT image formed by irradiation of first energy level radiation and a second energy level CT image formed by irradiation of second energy level radiation, applies a plurality of weighted computations to the first and second energy level CT images to compute a plurality of monochromatic CT images as a result of the weighted computations, segments a surrounding region of a highly-absorbent material circumferentially into a plurality of regions of interest having a predetermined area and calculates a standard deviation of the surrounding region by using a mean value of image data of each region of interest, for each monochromatic CT image, and selects a monochromatic CT image with a small standard deviation.

Abstract: Described herein is a medical linear accelerator including an accelerator target structure constructed of a material having a thickness of less than 0.2 radiation lengths, and an accelerator structure to receive an electromagnetic wave and generate an output therapy dose rate of electrons having a beam energy between 4-25 mega-electronvolts (MeV).

Abstract: An image processing system (IPS) and a related method. The system comprises an input interface (IN) for receiving two or more input images that include respectively an attenuation signal of an imaged object and a dark-field signal of the object. A combiner (COM) is configured to combine the two or more input images in a linear combination operation to form a combined image. An output (OUT) port configured to output the combined image.

Abstract: An X-ray scattering apparatus has a sample holder for aligning and orienting a sample to be analyzed by X-ray scattering, an X-ray beam delivery system arranged upstream of the sample holder for generating and directing a direct X-ray beam along a propagation direction towards the sample holder, a proximal X-ray detector arranged downstream of the sample holder as to let the direct X-ray beam pass and detect X rays scattered from the sample, and a distal X-ray detector arranged downstream of the sample holder and movable along the propagation direction (X) of the direct X-ray beam in which the proximal X-ray detector is also movable essentially along the propagation direction of the direct X-ray beam.

Abstract: A system for locating and tracking an object is provided. The system includes a measuring device configured to determine a property of a paving-related material, a locating device configured to determine a location of the measuring device, a tracking system configured to store tracking information associated with the measuring device and one or more properties determined by the measuring device, and a communications system configured to transfer, to a remote device, the location of the measuring device and the tracking information associated with the measuring device.

Abstract: An interactive rapid response Internet accessed air travel management system. The system includes a web-based planning and reservation interface system and an interactive access device. The system responds to details of a member's desired travel, to thereafter act in real time to contact the domains of associated travel service providers to arrange for every aspect of the member's trip, from airline and hotel reservations, ticket issuance, and ground transportation, to restaurant and theater reservations, and any other travel related needs of the member. The system stores identification information to verify access device possession to prohibit unauthorized use of the system and to provide security pre-clearance to system members.

Abstract: The present disclosure relates to an imaging device for use in vehicle security check and a method therefor, and belongs to the field of security check. The imaging device for use in vehicle security check includes: a radiation source device including a first ray unit configured to emit a first ray beam by a first predetermined spread angle to allow the first ray beam to penetrate a first part of a vehicle to be inspected passing through an inspection lane at a preset speed; and a detector device including a first detector unit arranged corresponding to the first ray unit, and configured to receive the first ray beam. The radiation source device is at least partially arranged on the road surface of the inspection lane, and the first detector unit is arranged at a first side of the inspection lane.

Abstract: Described herein is a medical accelerator target including a target constructed of a material having an atomic number that is greater than or equal to 40 or having a thickness of less than 0.2 radiation lengths.

Abstract: A method includes forming a test key. The formation of the test key includes forming a first plurality of semiconductor strips, and cutting the first plurality of semiconductor strips into an array of a second plurality semiconductor strips, with each row of the array being formed from one strip in the first plurality of semiconductor strips, forming isolation regions in recesses between the second plurality of semiconductor strips, and recessing the isolation regions. The top portions of the second plurality of semiconductor strips protrude higher than the isolation regions form semiconductor fins, which form a fin array. An X-ray beam is projected on the test key. A diffraction pattern is obtained from scattered X-ray beam scattered from the test key.

Abstract: Methods and systems for measuring periodic structures using multi-angle X-ray reflectance scatterometry (XRS) are disclosed. For example, a method of measuring a sample by X-ray reflectance scatterometry involves impinging an incident X-ray beam on a sample having a periodic structure to generate a scattered X-ray beam, the incident X-ray beam simultaneously providing a plurality of incident angles and a plurality of azimuthal angles. The method also involves collecting at least a portion of the scattered X-ray beam.

Abstract: Provided is a radiation irradiation device that can improve the degree of freedom of an arm part and can reduce the number of noise suppression components, such as a ferrite core. A radiation irradiation device includes a radiation generating part having a radiation source that generates radiation; an arm part having the radiation generating part attached to one end thereof; and a main body part having the other end of the arm part connected thereto. The main body part has a power source part including a three-phase inverter circuit. The power source part supplies a three-phase alternating current voltage to the radiation generating part via the arm part.

Abstract: The present disclosure discloses an inspection device, an inspection method and an inspection system. The device comprises a distributed ray source comprising multiple source points; a light source collimator configured to converge the rays generated by the distributed ray source to form an inverted fan-shaped ray beam; a scatter collimator configured to only allow rays scattered at one or more particular scattering angles which are generated by the rays from the light source collimator interacting with inspected objects to pass; at least one detector each comprising multiple detection units which have an energy resolution capability and are substantially arranged in a cylindrical surface to receive the scattered rays passing through the scatter collimator; and a processing apparatus configured to calculate energy spectrum information of the scattered rays from the inspected objects based on a signal output by the detectors.

Abstract: The invention relates to a method for ascertaining a net weight of a product in a product range, plurality of contiguous product ranges form a product chain and a total weight of the product chain is ascertained. The product chain is X-rayed to ascertain values that correspond to the radiation that penetrates a defined range of the product chain. The ascertained values are used to ascertain a total value for the entire product chain. A product range with a single product is selected by means of evaluation of the ascertained values. A value of the product range is formed from the ascertained values. A gross weight of the product range is ascertained therefrom. The net weight used for the single product is approximately the weight or the net weight is ascertained from the difference between the weight and a prescribed or ascertained weight of the product range without a product.

Abstract: An apparatus for integrating metrology and method for using the same are disclosed. The apparatus includes a multi-chamber system having a transfer chamber, a deposition chamber, an etch chamber and a metrology chamber, and a robot configured to transfer a substrate between the deposition chamber or etch chamber and the metrology chamber.

Abstract: The present specification describes a compact, hand-held probe or device that uses the principle of X-ray backscatter to provide immediate feedback to an operator about the presence of scattering and absorbing materials, items or objects behind concealing barriers irradiated by ionizing radiation, such as X-rays. Feedback is provided in the form of a changing audible tone whereby the pitch or frequency of the tone varies depending on the type of scattering material, item or object. Additionally or alternatively, the operator obtains a visual scan image on a screen by scanning the beam around a suspect area or anomaly.

Abstract: According to one embodiment, the X-ray tube generates X-rays. The X-ray detector detects the X-rays transmitted through a subject. The data acquisition circuitry acquires count data concerning a count number of the detected X-rays for energy bands. The memory circuitry stores data of a response function that associates incident X-rays on the X-ray detector with a response characteristic of a system including the X-ray detector and the data acquisition circuitry. The processing circuitry calculates an X-ray absorption amount of each of a plurality of base substances based on the count data concerning the energy bands acquired by the data acquisition circuitry, an energy spectrum of the incident X-rays, and the response function.

Abstract: The invention relates to the field of the analysis of objects by x-ray diffraction spectroscopy. One subject of the invention is a device for analyzing an object by x-ray diffraction spectroscopy, comprising a collimator the shape of which allows various portions of an object to be analyzed simultaneously. To do this, the collimator includes channels inclined with respect to an axis, called the central axis of the collimator, in such a way that various channels address various elementary volumes distributed through the object. Another subject of the invention is a method allowing an object to be analyzed using such a device. The object may for example be a biological tissue that it is desired to characterize non-invasively and non-destructively.

Abstract: An individual access control portal includes two panels or columns that define a through corridor, which panels or columns are equipped with sensors designed to detect substances or materials liable to be carried by individuals travelling through the portal, wherein the portal is equipped with a plurality of detection barriers distributed along the direction of passage through the portal and logic means attached to the plurality of barriers, firstly to determine from the series of activations of the barriers, the place and movement of an individual and secondly to establish the correlations existing between the movement of an individual and the signals output by the substance or material detection sensors.

Abstract: A scanning method, which is a method of identifying a change in the density of an object, includes arranging a source of ionizing radiation and an array of radiation detectors Dn, where n is an integer from 1 to N, capable of detecting the radiation in such a way that radiation counts are counted by the detectors as the source and detectors are rotated around the object. Detectors are arranged in conjugate pairs so that missing data due to a malfunctioning detector may be filled in from its conjugate.

Abstract: A system and method for foreign object detection in meat processing is provided. The system and method combine microfocus X-ray tubes with dual energy X-rays to detect foreign objects in meat products. A dual energy image processing algorithm analyzes the dual energy X-rays passed through the meat product to identify the foreign object present therein. An alarm or other notification is then generated in response to the detection of a foreign object.

Abstract: An X-ray computed tomography apparatus according to embodiments includes image processing circuitry and decomposition circuitry. The image processing circuitry is configured to perform an image processing on each of a plurality of pieces of monochromatic X-ray image data of different energies, the plurality of pieces of monochromatic X-ray image data being generated from projection data. The decomposition circuitry is configured to decompose, for each of a plurality of basis materials specified in advance, the plurality of pieces of monochromatic X-ray image data after the image processing, to generate basis material image data of each of the plurality of basis materials.

Abstract: A position-measuring device includes: a first subassembly having a measuring standard on which at least one coded track is provided, and a scanning unit, which is able to generate position signals that may be used to generate an absolute digital position value by scanning the at least one coded track in a measuring direction; a second subassembly having at least one peripheral unit adapted to execute a supplementary or an auxiliary functionality of the position-measuring device; and a plurality of electrical lines, which connect the first subassembly and the second subassembly to each other for the transmission of electrical signals. The position-measuring device is able to be operated in an initialization mode and in a standard operating mode. All components of the first subassembly required for the operation in the standard operating mode are components that are suitable for use in a radiation region of a machine.

Abstract: A method and apparatus are presented. X-rays are directed at a workpiece. The workpiece includes a fastener installed in an opening. Backscatter is received from the workpiece. It is determined if the fastener installed in the opening has an out of tolerance gap using the backscatter. An output is generated if the fastener installed in the opening has the out of tolerance gap.

Abstract: The X-ray CT apparatus includes an X-ray tube, a high-voltage power supply, an X-ray detector and a processing circuitry. The processing circuitry reconstructs, as a first image, any of a monochromatic X-ray image and a polychromatic X-ray image on a basis of pre-reconstruction data acquired by scanning an object, the polychromatic X-ray image being taken in a first X-ray energy band. The processing circuitry reconstructs, as a second image, a polychromatic X-ray image taken in a second X-ray energy band wider than the first X-ray energy band on a basis of a pre-reconstruction data acquired by scanning the object. The processing circuitry identifies an area of a correction target in the first image as a correction area. The processing circuitry corrects the correction area in the second image on a basis of the first image.

Abstract: The inventive body scanner is used to screen persons entering a security controlled area for the presence of security threats hidden under the clothing, such as guns, knifes, explosives and contraband. The Invention is an improvement on prior art body scanners that operate primarily by acquiring backscatter x-ray images, but only acquire transmission images over a limited part of the person's body. These prior art systems provide x-ray sources on the anterior and posterior sides of the person being screened, and x-ray sensitive detectors on the sides of these x-ray sources. While sufficient for backscatter imaging, the gaps between these detectors results in blind areas in the transmission images, resulting in lower ability to detect security threats hidden under the clothing. The present Invention overcomes these limitations of the prior art by providing x-ray sensitive detector on the outside of the x-ray sources.

Abstract: A method for analyzing an object includes measuring a first reflectivity of light from a surface and measuring a second reflectivity of light from the object, after the object is formed on the surface. A variation between the first and second reflectivities is calculated, and the variation is transformed by a predetermined transform. A thickness of the object is determined based on the transformed variation.

Abstract: The invention relates to a method and an apparatus for studying the X-ray properties of samples (3c), wherein X-ray radiation scattered by a sample (3c) is recorded by a detector (5) positioned at a distance from the sample (3c) and is evaluated with respect to the characteristics of the sample. According to the invention, it is provided that at a predetermined distance between the X-ray beam source (1) and the detector (5) or between the starting point (2b) of the X-ray beam (10) directed at the sample (3c) and the detector (5), for a predetermined number of successive measurements the distance (S1, S2) between the sample (3c) and the detector (5) is changed and is set at a predetermined different value.

Abstract: A radiographic imaging system includes an imaging unit that detects radiation transmitted through a subject, an operation unit that controls the imaging unit, a signal sending and receiving device connects the imaging unit and the operation unit to each other by wired or wireless communication. A signal reception state display unit is disposed in the imaging unit or the signal sending and receiving device so as to display a signal reception state indicative of communication between the imaging unit and the signal sending and receiving device.

Abstract: The present invention provides a method for evaluating energy loss in a polymeric material, wherein the method provides sufficient evaluation of the difference in performance between samples with excellent measurement accuracy; a method for evaluating chipping resistance of a polymeric material, wherein the method provides evaluation in a short period of time and at low cost with excellent measurement accuracy; and a method for evaluating abrasion resistance of a polymeric material, wherein the method provides sufficient evaluation of the difference in performance between samples with excellent measurement accuracy. The present invention relates to methods for evaluating energy loss, chipping resistance, and abrasion resistance of a polymeric material, and the methods include irradiating the polymeric material with X-rays or neutrons to perform X-ray scattering measurement or neutron scattering measurement.

Abstract: An X-ray examination station includes a first source of X-ray radiation for whole body scanning of a human body using a first fan beam of X-ray radiation; a first vertical linear radiation detector configured to detect the first fan beam; a second source of X-ray radiation installed at mid-height of a person being examined, for scanning a central portion of the human body using a second fan beam of X-ray radiation; a second vertical detector of X-ray radiation configured to detect the second fan beam; and a control unit configured to turn on each of the X-ray radiation sources. The first and the second radiation fan beams are emitted in parallel planes. The first X-ray radiation source is turned on for the whole body scanning. The second X-ray radiation source is turned on for scanning the central portion of the body.

Abstract: The invention relates to a device for identifying a material of an object having a source of X-Ray photons and a spectrometric detector, the source irradiating the object with an incident beam and the detector measuring a magnitude of a backscattered beam from the incident beam after scattering in a volume (?V) of the material and an energy of the X-Ray photons of the backscattered beam. The incident and backscattered beams forming a scattering angle (?). An adjusting device adjusts the position between the source, the detector and the object in order for the volume to be at different depths with a constant angle. A processing device processes the two magnitudes in two positions and the energy in one position and calculates an attenuation coefficient (?material (E0, E1, ?)). An estimating device estimates the density (?) of the material.

Abstract: Technologies pertaining to backscatter x-ray scanning systems are described herein. The backscatter x-ray scanning system includes an x-ray source, which directs collimated x-rays along a plurality of output vectors towards a target. A detector detects diffusely reflected x-rays subsequent to respective collimated x-rays impacting the target, and outputs signals indicative of parameters of the detected x-rays. An image processing system generates an x-ray image based upon parameters of the detected x-rays, wherein each pixel in the image corresponds to a respective output vector. A user selects a particular portion of the image, and a tool is positioned such that its directional axis is coincident with the output vector corresponding to at least one pixel in the portion of the image.

Abstract: A method and apparatus for inspecting an object. A radiation generation system is configured to emit radiation. A detector system is configured to detect backscatter formed in response to the radiation encountering the object. A redirection system is positioned relative to the detector system and is configured to redirect the backscatter to the detector system.

Abstract: A system for the inspection of the internal structure of a target includes at least one x-ray source that emits collimated x-rays to irradiate the target. At least one detector is positioned to detect backscatter x-rays from the target. The detector may include a collimation slot that limits the field of view of the detector. The target may be a railway component and the system may inspect the internal structure of the component as it is moved along the railway by a vehicle. The system may detect a change in the density of a target based on a comparison of the detected backscatter x-rays. The use of a plurality of segmented backscatter x-ray detectors having a collimation slot may pixelate the internal image in the direction of the collimation slot.

Abstract: An imaging system exposes an object within a region to a beam of penetrating radiation. The beam of penetrating radiation is sensed on a side opposite the region from a source of the beam. An attenuation of the beam caused by passing the beam through the object is determined, the attenuation is compared to a threshold attenuation. If the attenuation exceeds the threshold attenuation, a parameter of the imaging system is adjusted based on the determined attenuation.

Abstract: Disclosed are apparatus and methods for determining overlay error in a semiconductor target. For illumination x-rays having at least one angle of incidence (AOI), a correlation model is obtained, and the correlation model correlates overlay error of a target with a modulation intensity parameter for each of one or more diffraction orders (or a continuous diffraction intensity distribution) for x-rays scattered from the target in response to the illumination x-rays. A first target is illuminated with illumination x-rays having the at least one AOI and x-rays that are scattered from the first target in response to the illumination x-rays are collected. An overlay error of the first target is determined based on the modulation intensity parameter of the x-rays collected from the first target for each of the one or more diffraction orders (or the continuous diffraction intensity distribution) and the correlation model.

Abstract: The present invention relates to a method and a device for identifying unknown substances in an object. According to the state of the art a collimated X-ray beam is directed onto the object and X-ray energy scattered from the object is detected and measured. The measurement values detected are compared to known measurement values corresponding to specific substances or classes of substances to identify unknown substances in the object.

Abstract: An X-ray imaging system is provided with an X-ray source (11), first and second absorption gratings (31, 32), and a flat panel detector (FPD) (30), and obtains a phase contrast image of an object H by performing imaging while moving the second absorption grating (32) in x direction relative to the first absorption grating (31). The following mathematical expression is satisfied where p1? denotes a period of a first pattern image at a position of the second absorption grating (32), and p2? denotes a substantial grating pitch of the second absorption grating (32), and DX denotes a dimension, in the x-direction, of an X-ray imaging area of each pixel of the FPD (30). Here, “n” denotes a positive integer.

Abstract: A technique for use in security screening and detection contexts employs an X-ray explosive imager that acquires images from backscattered RF modulated X-ray signals on which a time series analysis is performed to detect image change across the time series of images that represent pixels changing at the rate of the difference frequency of the RF frequency and the a priori NQR signature frequencies.

Abstract: This invention has one object to provide radiographic apparatus with a compensating filter that allows simple and accurate estimation of direct radiation to acquire a radioscopic image or a sectional image of excellent contrast. This invention includes a direct-ray attenuation-rate acquiring section for acquiring a direct-ray attenuation rate from a dose of direct radiation entering into a subject and a dose of direct radiation emitted from the subject. In this invention, a direct-ray attenuation rate is acquired on an assumption that a primary indirect-ray attenuation rate is equal to the direct-ray attenuation rate, the primary indirect-ray attenuation rate being a rate of decreasing a primary indirect-ray generated with the compensating filter that transmits the subject. Such configuration may achieve provision of X-ray apparatus that allows more simple acquisition of a fluoroscopic X-ray image or a sectional image without performing complicated calculations conventionally.

Abstract: Peak positions and integrated intensities of diffraction X-ray are determined on the basis of X-ray diffraction measurement data output from an X-ray diffractometer, the number of determined peaks of the diffraction X-ray is counted, and analysis processing is started when the counted number of peaks reaches a preset peak number. The analysis processing is repetitively executed on the basis of X-ray diffraction measurement data. The peak positions and the integrated intensities of the diffraction X-ray are determined from the X-ray diffraction measurement data obtained from the start of the measurement till the analysis processing concerned, and qualitative analysis of collating the determined peak positions and integrated intensities with standard peak card data whose data base is made in advance and searching materials contained in a measurement sample, and quantitative analysis of determining the quantities of the materials contained in the measurement sample are executed.

Abstract: In accordance with an embodiment, a measuring apparatus includes an electromagnetic wave applying unit, a detecting unit, a data processing unit, a film structure transforming unit, and a film structure measuring unit. The electromagnetic wave applying unit generates electromagnetic waves to apply it to a periodic structure of films on a substrate. The detecting unit detects the electromagnetic waves scattered or reflected by the substrate. The data processing unit calculates a surface shape of the periodic structure. The film structure transforming unit calculates a virtual film structure regarding the internal structure of the periodic structure. The film structure measuring unit calculates the thickness of each layer constituting the periodic structure by fitting a first reflectance profile by actual measurement regarding the periodic structure to a second reflectance profile obtained by a simulation using the virtual film structure to restructure the shape of the periodic structure.

Abstract: Embodiments of backscatter inspection systems include features to enable inspection of irregular surfaces, tight spacer, and other hard-to-reach places. Some embodiments include arms that maneuver a scan head with at least three degrees of freedom, and some embodiments include arms that maneuver a scan head with at least seven degrees of freedom. Some embodiments include proximity detectors on a scan head or base, detect contact with an object being inspected, and to slow or stop the motion of the system accordingly. Some compact embodiments scan the interior of an object from within, and include a rotating, low-energy source of penetrating radiation, and at least one backscatter detector, which may be stationary, or may rotate with the source.