397 results about "Scattering radiation" patented technology

A system for treating a selected dermatologic problem and a head for use with such system are provided. The head may include an optical waveguide having a first end to which EM radiation appropriate for treating the condition is applied. The waveguide also has a skin-contacting second end opposite the first end, a temperature sensor being located within a few millimeters, and preferably within 1 to 2 millimeters, of the second end of the waveguide. A temperature sensor may be similarly located in other skin contacting portions of the head. A mechanism is preferably also provided for removing heat from the waveguide and, for preferred embodiments, the second end of the head which is in contact with the skin has a reflection aperture which is substantially as great as the radiation back-scatter aperture from the patient's skin. Such aperture may be the aperture at the second end of the waveguide or a reflection plate or surface of appropriate size may surround the waveguide or other light path at its second end. The portion of the back-scattered radiation entering the waveguide is substantially internally reflected therein, with a reflector being provided, preferably at the first end of the waveguide, for returning back-scattered light to the patient's skin. The reflector may be angle dependent so as to more strongly reflect back scattered light more perpendicular to the skin surface than back scattered radiation more parallel to the skin surface. Controls are also provided responsive to the temperature sensing for determining temperature at a predetermined depth in the patient's skin, for example at the DE junction, and for utilizing this information to detect good thermal contact between the head and the patient's skin and to otherwise control treatment. The head may also have a mechanism for forming a reflecting chamber under the waveguide and drawing a fold of skin therein, or for providing a second enlarged waveguide to expand the optical aperture of the radiation.

A system includes acquisition of a three-dimensional cone beam image, and determination of a dose to be delivered based on the three-dimensional image and on parameters of a treatment beam to deliver the dose. Some systems may include modification of a three-dimensional cone beam image to correct for scatter radiation, and determination of a dose based on the modified three-dimensional cone beam image.

Systems and methods for fast and sensitive standoff surface-hazard detection with high data throughput, high spatial resolution and high degree of pointing flexibility. The system comprises a first hand-held unit that directs an excitation beam onto a surface that is located a distance away from the first unit and an optical subsystem that captures scattered radiation from the surface as a result of the beam of light. The first unit is connected via a link that includes a bundle of optical fibers, to a second unit, called the processing unit. The processing unit comprises a fiber-coupled spectrograph to convert scattered radiation to spectral data, and a processor that analyzes the collected spectral data to detect and/or identify a hazardous substance. The second unit may be contained within a body-wearable housing or apparatus so that the first unit and second unit together form a man-portable detection assembly. In one embodiment, the system can continuously and without interruptions scan a surface from a 1-meter standoff while generating Raman spectral-frames at rates of 25 Hz.

Metrology targets are formed on a substrate (W) by a lithographic process. A target (T) comprising one or more grating structures is illuminated with spatially coherent radiation under different conditions. Radiation (650) diffracted by from said target area interferes with reference radiation (652) interferes with to form an interference pattern at an image detector (623). One or more images of said interference pattern are captured. From the captured image(s) and from knowledge of the reference radiation a complex field of the collected scattered radiation at the detector. A synthetic radiometric image (814) of radiation diffracted by each grating is calculated from the complex field. From the synthetic radiometric images (814, 814′) of opposite portions of a diffractions spectrum of the grating, a measure of asymmetry in the grating is obtained. Using suitable targets, overlay and other performance parameters of the lithographic process can be calculated from the measured asymmetry.

Blood cells of interest are readily distinguishable from other blood cells and look-a-like particles found in a blood sample by their back-scatter signature. A preferred method for differentiating platelets in a blood sample is to irradiate the cells and particles, one at a time, with a beam of radiation, and to detect back-scattered (reflected) radiation using a plurality of optical fibers to transmit the back-scattered radiation to a high-gain photodetector, e.g. a photomultiplier tube. Preferably, the back-scatter signal so obtained is combined with a second signal representing, for example, either the level of forward-scatter within a prescribed, relatively narrow angular range, or the level of side-scattered radiation, or the level of attenuation of the cell-irradiating beam caused by the presence of the irradiated cell or particle in the beam, or the electrical impedance of the irradiated cell or particle, to differentiate the cells of interest. The method and apparatus of the invention are particularly useful in differentiating platelets and basophils in a blood sample.

A method of using LIDAR on an airborne vehicle is described. A beam of radiation is transmitted to target areas at least one of above, below, and in front of the airborne vehicle, the target areas including particles or objects. Scattered radiation is received from the target areas. Respective characteristics of the scattered radiation are determined. Air turbulence factor or characteristics are determined from the respective characteristics. The airborne vehicle is controlled based on the air turbulence factor, such that turbulence experienced by the airborne vehicle is minimized. Alternatively, the airborne vehicle is controlled based on the characteristics to avoid colliding with the one or more objects. In another example, the airborne vehicle is controlled based on the characteristics to reduce headwind or increase tailwind, and substantially reduce a carbon footprint of the aircraft.

A method for performing scattered radiation correction. The position of a collimator and the width of a slit are adjusted so that direct radiation will fall on one of a plurality of arrays of detectors. A predetermined phantom is scanned. The scan is performed relative to each of the plurality of arrays of detectors. Based on data detected during each scan, scattered radiation correction data is produced. The produced scattered radiation correction data is used to correct projection data acquired by scanning a subject.

An array of antenna elements (20) can be used to detect subwavelength sized anomalies on a surface below the array. An array (20) is illuminated at optical frequencies by a coherent optical energy source (26). The change in reactance and radiated power of the antenna elements that results from the proximity of the anomaly to the near field of the antenna element's open-circuited is detected and holographically filtered to eliminate the radiation caused by the antenna array itself. Image processing is performed on the detected scattered radiation (100) to determine whether an anomaly is present and to locate the anomaly and its characteristics.

X-ray radiation is transmitted through and scattered from an object under inspection to detect weapons, narcotics, explosives or other contraband. Relatively fast scintillators are employed for faster X-ray detection efficiency and significantly improved image resolution. Detector design is improved by the use of optically adiabatic scintillators. Switching between photon-counting and photon integration modes reduces noise and significantly increases overall image quality.

A device for performing distance measurements on an eye. The device includes an interferometer, focuses at least one measurement beam records backscattered radiation and interferometrically generates a measurement signal displaying structures of the eye by time-domain, spectral-domain or Fourier-domain coherence reflectometry, has an adjustment apparatus for laterally and/or axially displacing the focus in the eye or for varying a polarization state of the measurement beam and has a control apparatus which actuates the interferometer, wherein the control apparatus generates a plurality of A-scan individual signals from the backscattered radiation, combines these to an A-scan measurement signal and actuates the adjustment apparatus for displacing the position of the focus or for varying the polarization while recording the backscattered radiation from which the control apparatus generates the A-scan individual signals is being recorded.

A method for calibrating an imaging system includes coincident detecting scatter radiation events from a calibration source located within a bore of the imaging system. The scatter radiation events are subsequently used to compute calibration time offsets for each detector channel in the imaging system. Each detector channel is then calibrated with respective calibration time adjustments.

This invention involves measurement of optical properties of materials with sub-micron spatial resolution through infrared scattering scanning near field optical microscopy (s-SNOM). Specifically, the current invention provides substantial improvements over the prior art by achieving high signal to noise, high measurement speed and high accuracy of optical amplitude and phase. Additionally, it eliminates the need for an in situ reference to calculate wavelength dependent spectra of optical phase, or absorption spectra. These goals are achieved via improved asymmetric interferometry where the near field scattered light is interfered with a reference beam in an interferometer. The invention achieves dramatic improvements in background rejection by arranging a reference beam that is much more intense than the background scattered radiation. Combined with frequency selective demodulation techniques, the near-field scattered light can be efficiently and accurately discriminated from background scattered light. These goals are achieved via a range of improvements including a large dynamic range detector, careful control of relative beam intensities, and high bandwidth demodulation techniques.

A CT scanner with scatter correction device and a method for scatter correction are provided. The method of correcting CT images from artifacts caused by scattered radiation comprises affixing to the non-rotating frame of the CT gantry a plurality of shields for shielding some of the CT detector elements from direct X ray radiation, while allowing scattered radiation to arrive at said shielded elements; measuring scatter signals from said shielded elements, indicative of scattered radiation intensity; and correcting for scatter by subtracting scatter intensity values estimated from said measured scatter signals from signals measured by unshielded detector elements.

A detection system includes a multi-focus radiation source configured to generate X-ray radiation and a primary collimator defining a first row of apertures and a second row of apertures. The first row of apertures forms first X-ray beams within a first plane from the X-ray radiation, and the second row of apertures forms second X-ray beams within a second plane from the X-ray radiation. The first plane is different than the second plane. The detection system further includes a scatter detector including a first row of scatter detector elements and a second row of scatter detector elements. The first row of scatter detector elements is configured to detect scattered radiation from the first X-ray beams, and the second row of scatter detector elements is configured to detect scattered radiation from the second X-ray beams.

Disclosed is a method of measuring a target, an associated substrate, a metrology apparatus and a lithographic apparatus. In one arrangement the target comprises a layered structure. The layered structure has a first target structure in a first layer and a second target structure in a second layer. The method comprises illuminating the target with measurement radiation. Scattered radiation formed by interference between plural predetermined diffraction orders is detected. The predetermined diffraction orders are generated by diffraction of the measurement radiation from the first target structure and are subsequently diffracted from the second target structure. A characteristic of the lithographic process is calculated using the detected scattered radiation formed by the interference between the predetermined diffraction orders.