Abstract: A method for measurement of critical dimensions includes irradiating a surface of a substrate with a beam of X-rays. A pattern of the X-rays scattered from the surface due to features formed on the surface is detected and analyzed to measure a dimension of the features in a direction parallel to the surface.

Abstract: Reflectometry apparatus includes a pulsed X-ray source, adapted to irradiate a sample with a sequence of pulses of radiation over a range of angles relative to a surface of the sample. An array of detector elements is positioned to receive the radiation reflected from the sample over the range of angles and to generate a signal indicative of respective charges accumulated by the detector elements due to photons of the radiation that are incident on the elements. Timing circuitry is coupled to the array so as to cause the charges to be cleared from the detector elements immediately before each of the pulses in the sequence, and to cause the signal from the elements to be sampled shortly after each of the pulses.

Abstract: Reflectometry apparatus includes a radiation source, adapted to irradiate a sample with radiation over a range of angles relative to a surface of the sample, and a detector assembly, positioned to receive the radiation reflected from the sample over the range of angles and to generate a signal responsive thereto. A shutter is adjustably positionable to intercept the radiation, the shutter having a blocking position, in which it blocks the radiation in a lower portion of the range of angles, thereby allowing the reflected radiation to reach the array substantially only in a higher portion of the range, and a clear position, in which the radiation in the lower portion of the range reaches the array substantially without blockage.

Abstract: A method of X-ray analysis includes irradiating a spot on a sample with X-rays along an X-ray beam axis. X-rays emitted from the sample, responsive to irradiating the spot, are simultaneously detected at a plurality of different azimuthal angles relative to the beam axis. X-ray intensities detected at the different angles in a common energy range are compared in order to determine a property of the sample.

Abstract: Apparatus for X-ray analysis of a sample includes an X-ray source, which irradiates the sample, and an X-ray detector device, which receives X-rays from the sample responsive to the irradiation. The device includes an array of radiation-sensitive detectors, which generate electrical signals responsive to radiation photons incident thereon. Processing circuitry of the device includes a plurality of signal processing channels, each coupled to process the signals from a respective one of the detectors so as to generate an output dependent upon a rate of incidence of the photons on the respective detector and upon a distribution of the energy of the incident photons.

Abstract: Apparatus for X-ray microanalysis of a sample includes an X-ray source, which irradiates a spot having a dimension less than 500 &mgr;m on a surface of the sample. A first X-ray detector captures fluorescent X-rays emitted from the sample, responsive to the irradiation, at a high angle relative to the surface of the sample. A second X-ray detector captures X-rays from the spot at a grazing angle relative to the surface of the sample. Processing circuitry receives respective signals from the first and second X-ray detectors responsive to the X-rays captured thereby, and analyzes the signals in combination to determine a property of a surface layer of the sample within the area of the spot.

Abstract: A method for testing the deposition and/or the removal of a material within a recess on the surface of a sample. An excitation beam is directed onto a region of the sample in a vicinity of the recess, and an intensity of X-ray fluorescence, emitted from the region in a spectral range in which the material is known to fluoresce, is measured. A quantity of the material that is deposited within the recess is determined responsive to the measured intensity.

Abstract: A method and apparatus for detecting a contaminant in a substrate. An array of anode elements is positioned in proximity to the substrate and is biased at a positive voltage relative to the substrate. The substrate is irradiated with photons having energies below an atomic ionization energy of the substrate, so as to ionize the contaminant to emit electrons. The emitted electrons are collected at one or more of the anode elements, thereby generating a current indicative of the presence of the contaminant in the semiconductor in proximity to the one or more of the anode elements.

Abstract: An x-ray fluorescent analyzer and method for analyzing a sample, including an x-ray beam generator, which generates an x-ray beam incident at a spot on the sample, and creates a plurality of fluorescent x-ray photons. There are a plurality of semiconducting detectors arrayed around the spot so as to capture the fluorescent x-ray photons and in response produce a plurality of electrical pulses suitable for analysis of the sample.

Abstract: Apparatus for X-ray excitation of a sample, including a substantially stationary X-ray source and X-ray optics, including at least one secondary target and a movable element. The movable element has at least a first position wherein X-rays emitted by the source excite the sample directly, and a second position wherein X-rays emitted by the source strike the at least one secondary target, causing the secondary target to emit X-rays that excite the sample, while the X-rays emitted by the source are substantially prevented from exciting the sample.

Abstract: Apparatus for optical analysis of a sample, including an energy source, which generates a pulse of energy that is incident on the sample, causing the sample to emit radiation characteristic of the composition of the sample, and a detector assembly, which receives and analyzes the radiation emitted by the excited sample. An optical assembly conveys the emitted radiation from the sample to the detector assembly, the optical assembly including an optic proximal to the sample, on which optic the radiation is incident along a beam path thereof between the sample and the detector assembly. A moving mechanical element moves in synchronization with the pulse from the energy source so as to substantially prevent matter ejected from the sample responsive to the incident energy from accumulating on the optic.

Abstract: A radio frequency transmission line filter has an insulative substrate substantially in the form of a plate of dielectric material, a ground plane formed by metallization on one face of the substrate, capacitor plates formed by areas of metallization on the other face of the substrate to form, in conjunction with the ground plane, capacitances, and coupled to the capacitances, respective metallized short circuit transmission line stubs forming inductances. The inductances and capacitances together form transmission line resonators. To allow the designer a wide choice in capacitance and/or inductance values, the substrate is recessed in selected areas to bring the ground plane to within predetermined distances of the capacitor plates or inductance stubs. The ground plane may be trimmed in the recessed areas to adjust component values.

Abstract: In order to supply a dose rate which is as constant as possible over the cross section of the x-ray cone for radiation therapy, especially at lesser tissue depths (e.g. 3 cm), the surfaces of the collimator which define the margin of the x-ray cone are roughened for example by means of grooves transverse to the radiation direction, the grooves having semicircular or step-shaped cross sectional configuration, and advantageously being formed in a thin walled sleeve of low atomic number.

Abstract: A beam defining system for an electron accelerator has an adjustable collimator with an accessory holder attached thereto for retaining an electron applicator. The electron applicator has an applicator wall which encloses an electron beam cone from the collimator. A frame-shaped spacer which can be brought into contact with the patient is attached to the applicator wall. A frame-shaped limiting aperture additional to limiting members in the collimator are provided on the applicator wall in order to limit the electron-beam cone at marginal regions facing away from the beam defining system.

Abstract: An ionization chamber for analyzing inhomogeneities in a radiated beam from a particle accelerator system has two measuring chambers formed by three mutually parallel walls spaced apart by spacer rings. Two of the three walls have single electrodes arranged thereon whereas a third wall has several mutually insulated electrodes applied on a measuring chamber side of the wall. The mutually insulated electrodes include a central circular electrode and a group of electrode segments arranged in circular fashion around the central electrode. Inhomogeneities in the radiation intensity of a beam being analyzed are detected by unequal currents in the central electrode relative to surrounding electrode segments or in the electrode segments themselves relative to each other.

Abstract: In an electron accelerator having a target which is subjected to an electron beam for the production of deceleration radiation, a collimator is provided behind the target which has a passageway adapted to receive a beam cone of maximum dimensions. Adjustable x-ray aperture plates are provided behind the collimator and an electron absorber is provided behind the target. An additional electron absorber is positioned in a widened portion at one end of the passageway in the collimator. Both electron absorbers are made of a material having a relatively low atomic number as compared with electron absorbers of the prior art.

Abstract: A monitoring system for the high-voltage supply of an ionization chamber of a particle accelerator has a measuring system which is free of hysteresis and which is electrically isolated from the high-voltage to be measured by opto-electronic couplers. The measuring system controls a switching member for supervising operation of the particle accelerator.

Abstract: In an electron accelerator having a target which is exposed to an electron beam for the production of x-ray deceleration radiation, a conical compensating member is arranged centrally within a cone pattern of the x-ray radiation. The compensating member has a decreasing conical shape toward the target and merges into a cylinder portion. Beam paths within the cylinder portion which are additional to those in a conventional purely conical compensating member are compensated by a recess positioned in a base of the compensating member having an appropriately selected depth. In another embodiment, a conically shaped compensating member is arranged within the cone-shaped x-ray pattern such that a tip of the compensating member is aligned away from the target and a base is aligned toward the target. A collimator having a conical passageway surrounding the x-ray radiation has a groove for receiving the base of the compensating member so as to mount the same within the conical passageway of the collimator.