The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 04, 2001
Filed:
Dec. 18, 1998
Carl A. Listl, New Hyde Park, NY (US);
David F. Lewis, Monroe, CT (US);
ISP Investments Inc., Wilmington, DE (US);
Abstract
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.