Isp Investments Inc.

Gaf Corporation

Henry Seiwatz

Carl A Listl

David F Lewis

J Michael Donahue

Sotiri A Papoulias

In a method for manufacturing a calibrated radiation dosimeter, a layer of radiation sensitive material is applied to a substrate, the radiation sensitive material having an optical density which varies in accordance with a degree of radiation exposure. A pre-exposure optical density of the layer of radiation sensitive material is optically measured and subsequently the layer of radiation sensitive material is exposed to a known dose of radiation. Thereafter, a post-exposure optical density of the layer of radiation sensitive material is optically measured. Using at least the pre-exposure optical density, the post-exposure optical density, and the known dose of radiation, one computes mathematical parameters defining a predetermined mathematical function. The computed mathematical parameters are applied in encoded form to the substrate (e.g., printed in bar code form on the substrate or a holder card).

Method for manufacturing calibrated radiation dosimeter

A method for determining a level of exposure to radiation utilizes a radiation dosimeter comprising a substrate provided with a radiation sensitive layer or patch having an optical density which varies in accordance with the degree of radiation exposure. In addition, the substrate is provided with optically readable coding which identifies one or more encoded mathematical parameters for enabling an automated calculation of dosage from a detected optical density change of the radiation sensitive material. In the method, the coding on the dosimeter substrate is scanned to automatically determine the encoded mathematical parameters, and a plurality of pre-exposure optical densities and a plurality of post-exposure optical densities of the layer of radiation sensitive material in a plurality of wavelength bands are optically measured. From these quantities, a quantitative radiation dose to which the layer of radiation sensitive material was exposed is automatically computed in accordance with a predetermined mathematical algorithm. Each dosimeter is provided with a unique identification code encoded in the bar coding on the dosimeter substrate, to enable memory storage of pre-exposure optical densities for multiple dosimeters.

Radiation dosimetry method and apparatus

A method for determining a level of exposure to radiation utilizes a radiation dosimeter comprising a substrate provided with a radiation sensitive layer or patch having an optical density which varies in accordance with the degree of radiation exposure. In addition, the substrate is provided with optically readable coding which identifies encoded mathematical parameters for enabling an automated calculation of dosage from a detected post-exposure optical density of the radiation sensitive material. The method comprises the step of optically measuring the optical density of the layer of radiation sensitive material prior to exposure thereof to radiation. In addition, the coding on the dosimeter substrate is scanned to automatically determine the encoded mathematical parameters. The method further comprises the steps of exposing the radiation sensitive layer to radiation and optically measuring a post-exposure optical density of the layer of radiation sensitive material. Subsequently, from the pre-exposure optical density, the post-exposure optical density, and the mathematical parameters and in accordance with a predetermined mathematical algorithm, a quantitative radiation dose to which the layer of radiation sensitive material was exposed is automatically computed. Preferably, the computed quantitative radiation dose is automatically indicated on a display. Each dosimeter may be provided with a unique identification code encoded in the bar coding on the dosimeter substrate, to enable memory storage of pre-exposure optical densities for multiple dosimeters. A look-up table may be stored in memory for enabling correction of computed optical densities where the post-exposure densities are measured at different times intervals after exposure.

A radar absorber, for use as a sprayable paint, or for use as a plastic sheet, is provided. The radar absorber is used to cover a structural part of an aircraft or to shield a part of a naval vessel. The absorber, or coating in this embodiment, includes an inner layer having an elastomeric carrier material with a carbonyl iron powder dispersed therein, or disposed therein, of a regular particle size of about 4 to 5 micron, and includes an outer layer having an elastomeric carrier material with a carbonyl iron powder dispersed therein, or disposed therein, of a fine particle size of about 0.5 to 1.5 micron.

Radar absorber

A retarding field spectrometer has a mounting ring for attachment to the pole piece of a scanning electron microscope or similar beam generator. Supported by the mounting ring are three screen electrodes with their planes positioned normal to the beam axis and adjustable as a unit in a pseudo-orthogonal manner through two worm and gear drives of eccentrics cooperating with an aperture and a slot, respectively, in a plate carrying the electrode closest to the pole piece. Three continuous dynode electron multipliers are arrayed symmetrically about the beam at-rest axis between the last mentioned electrode and the intermediate electrode. The multipliers have cathodes maintained at substantially the same potential as the intermediate electrode. The electrode furthest from the pole piece is suspended from a mounting ring for the intermediate electrode by means of criss-crossing strands of a continuous plastic monofilament permitting orthogonal adjustment of the furthest electrode relative to the intermediate electrode while insulating electrically one from the other.

Retarding field spectrometer

In the recording for a mass memory system by means of a plurality of electrostatic electron beam charges on an insulator storage medium comprising a dielectric material having a maximum secondary electron emission coefficient (.delta..sub.max) greater than one as a surface layer disposed on a conductive support the process of recording the individual transmission of charges at three distinguishable energy levels which provide uncharged spots and alternating negative and positive electrostatic charges in the pixels of the dielectric layer which alternating charges are effected by employing a primary beam energy greater than the lowest energy and less than the highest energy at which the secondary electron emission coefficient (.delta.) is unity for a positive charge and employing a primary beam energy less than the lowest energy or greater than the highest energy at which .delta. is unity for a negative charge.

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Wayne, NJ, United States of America

Henry Seiwatz