Isp Investments Inc.

Gaf Corporation

Gaf Chemicals Corporation

Carl A Listl

David F Lewis

Henry Seiwatz

J Michael Donahue

Xiang Y Yu

Mark L Moskowitz

Robert D Schenfele

Anthony Pilato

A radiation dosimetry method and associated devices for carrying out the method are disclosed herein. More particularly, a method and associated apparatus which compensates for variations in amounts of a radiation sensitive material in a radiation dosimetry film is provided.

Radiation dosimetry method

An article of manufacture comprising a radiation sensitive material, and a measuring scale that is part of the radiation sensitive material. A method of measuring at least one parameter relating to an irradiated material is also described. A radiation sensitive material including a measuring scale is exposed to radiation and at least one parameter relating to one or more exposed areas of the material is measured by reference to the measuring scale on the material.

Radiation sensitive film including a measuring scale

A method and associated apparatus for monitoring exposure to radiation, with compensation for temperature variation of a sensor and variations in the amount of radiation sensitive material in a dosimeter used in the method. The method utilizes a radiation dosimeter having a layer of radiation sensitive material on a substrate, the radiation sensitive material having an optical absorbance which varies in accordance with degree of radiation exposure and wavelength and which also varies in dependence on temperature. The radiation sensitive layer includes a substantially radiation impervious substance. The method comprises exposing the layer of radiation sensitive material to a dose of radiation, optically measuring a spectral absorbance of the exposed layer of radiation sensitive material within a range of wavelengths, examining the measured spectral absorbance of the exposed layer of radiation sensitive material to determine an absorbance coordinate and a wavelength coordinate of a predetermined point on a spectral absorbance curve of the exposed layer of radiation sensitive material, and determining a radiation dose value associated with the absorbance coordinate and the wavelength coordinate. Generally, the radiation dose value is determined by consulting a table of absorbance and wavelength coordinates with associated dose values which have been previously measured for a batch of the radiation sensitive material, the batch having a uniform absorbance coefficient and a common concentration of the radiation sensitive material. The method can automatically compensate for variations in the amount of radiation sensitive material by adjusting the absorbance value of the radiation sensitive material by a measured value of absorbance in the radiation impervious substance.

Radiation dosimetry method and associated apparatus

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 multi-ply radiation dosage indicator, and method of manufacture, is disclosed including a first ply having visible indicia thereon and a second ply having a radiation sensitive zone overlying the indicia of the first ply. The radiation sensitive zone is capable of changing opacity in response to exposure to a radiation dosage exceeding a predetermined threshold so as to change the visibility of the indicia thereby providing an indication as to whether the indicator has become irradiated. An optical filter ply may be provided overlying the indicia, and the indicator also may be provided with a transparent protective outer ply. A pressure sensitive adhesive ply having a removable release sheet is employed for attaching the indicator to a substrate.

Radiation dosage indicator

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.

Growing community of inventors

New Hyde Park, NY, United States of America

Carl A Listl