American Science and Engineering, Inc.

Allen S Krieger

Paul Burstein

Martin Annis

Klaus Kubierschky

John K Silk

Richard C Chase

Eugene W Huang

An x-ray detector includes a solid scintillating crystal of cadmium tungstate or bismuth germanate; the crystal is mounted in an x-radiation field and includes a first region directly exposed to the x-radiation. A protective shield is arranged adjacent the crystal so as to protect a region in space from direct exposure to x-radiation. The crystal includes a second component which is located in the protected region of space and is thus not exposed to direct x-radiation. Located in contact with opposing faces of the crystal are two pairs of photodiodes, the photodiodes themselves as well as the crystal faces with which they are in contact lie in the protected region in space and therefore are not exposed to direct x-radiation. The photodiodes themselves are also protected from scattered x-radiation by the protected component of the crystal. One pair of photodiodes has equal active areas, which is however different from the active areas of the other pair of photodiodes. All the photodiodes have anode and cathode leads, and corresponding leads for the diodes in each pair are connected together.

X-ray detector suited for high energy applications with wide dynamic

A high energy imaging system provides a 'slotted' or 'slot-shaped' or 'rectangular cross-section' beam of illumination to intercept an annular region of an object of revolution as it is rotated. A detector array is located to intercept the illumination beam emanating from the object. The detector array includes an opto-electric transducer imaging a plurality of scintillating optical fiber or fiber bundles. The optical fiber or fiber bundles are located substantially parallel to each other with longitudinal axes substantially perpendicular to the direction of the illuminating radiation and parallel to the longitudinal axis of the object being imaged.

Annular x-ray inspection system

Computerized axial tomography is employed with respect to large relatively dense objects such as a solid fuel rocket engine. High energy X-rays, such as a 15 MeV source is used. To develop clean images, a collimator is employed with a relatively minute acceptance angle. Acceptance angles on the order to 1.degree., and in a preferred embodiment 7 minutes of a degree, are used. In a preferred embodiment, the collimator may be located between the object and the detector, although in other embodiments, a pre-collimator may also be used, that is between the X-ray source and the object being illuminated.

High energy computed tomography

An apparatus for simultaneously obtaining both non-dispersive and spatially-resolved soft x-ray spectra from a distributed soft x-ray source. A charge coupled device (CCD) camera having a back-illuminated CCD is irradiated by an x-ray source and a mechanical shutter or electronic shutter effect is used to define an integration period for the pixels of the CCD that ensures that the probability of a single pixel receiving more than one photon during the integration period is small. The magnitude of the charge at each pixel over an integration period is stored in a memory device and, after a plurality of integration periods have passed, the stored data for each pixel may be individually analyzed or combined and displayed to image the x-ray source.

Soft x-ray spectrometric imaging system

An X-ray lithography system for the production of micro-electronic circuits, of the type comprising a mask having detailed circuit patterns thereon which are irradiated by soft X-rays onto a wafer covered with a photosensitive material to replicate the mask patterns, includes an X-ray source spaced from the mask and operative to produce a plurality of input beams of X-rays which are substantially collimated by an array of grazing incidence mirrors to produce a plurality of output X-ray beams which are spaced from one another at the output of the collimator and which are projected in substantially parallel relation to one another toward the mask. Each output beam exhibits a small divergence which causes the several output beams to merge into a single, comparatively large cross-sectional area, composite beam of X-rays at a plane spaced from the collimator. The mask is positioned substantially in said plane for illumination by the composite beam of X-rays. Filters are provided, preferably in the region between the mask and the collimator, for adjusting the spatial uniformity and spectrum of the composite beam.

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Lexington, MA, United States of America

Allen S Krieger