Radiation dose rate measurement
AssigneeBritish Nuclear Fuels plc
InventorsJohn Adrian Lightfoot, Karl Anthony Hughes
Life of this patent
Estimating the term…
Abstract
A method and apparatus are provided for determining radiation dose rates at selected locations within an environment. Incident gamma ray energy and count rate are measured at one or more measured locations within the environment to obtain a measured spectrum for those measured locations. The spatial position of the measured locations is also measured. An emitted spectrum is then determined for the measured locations based on the measured spectrum. The emitted spectrum may then be used to determine the dose rate at one or more selected locations (which may be different than the measured locations). In this way the invention provides an accurate solution for the dose rate at any point of interest within the environment based on the measured count and incident energies.
Claims16
A method for determining dose or dose rate for one or more selected locations within an environment, comprising the steps of:
- a) measuring incident gamma ray energy and count rate from one or more sources, for one or more viewed portions of the environment, at one or more measured locations within the environment to obtain one or more measured spectra for said measured locations;
- b) measuring the spatial position of each of said measured locations;
- c) determining an emitted spectrum for each said viewed portion of the environment from said measured spectrum for each said viewed portion of the environment;
- d) inputting the emitted spectra and said spatial position of said measured locations to data processor;
- and
- e) determining the dose or dose rate at one or more selected locations from a calculated total gamma ray energy incident on the one or more selected locations arising from the emitted spectrum of the one or more sources, wherein the measured spectra is divided into a series of energy ranges or bins, the count rates or counts falling within a range or bin are summed to give a total count rate or total count for that range or bin, the series of energy ranges or bins including a highest energy range or bin, where the highest energy range or bin is analyzed first, the analysis involving subtracting from the ranged or binned spectrum a value, the value being based on a response function multiplied by a variable factor to reduce the range or bin under analysis to zero.
A method for determining dose or dose rate for one or more selected locations within an environment, comprising the steps of:
- a) measuring incident gamma ray energy and count rate from one or more sources, for one or more viewed portions of the environment, at one or more measured locations within the environment to obtain one or more measured spectra for said measured locations;
- b) measuring the spatial position of each of said measured locations;
- c) determining an emitted spectrum for each said viewed portion of the environment from said measured spectrum for each said viewed portion of the environment;
- d) inputting the emitted spectra and said spatial position of said measured locations to data processor;
- and
- e) determining the dose or dose rate at one or more selected locations from a calculated total gamma ray energy incident on the one or more selected locations arising from the emitted spectrum of the one or more sources, wherein one or more of said selected locations are different from any of said measured locations, wherein an energy bin is analyzed by subtracting from a ranged or binned measured spectra a value based on a response function multiplied by a variable factor to reduce the bin under analysis to zero.
A dose or dose rate determining apparatus for one or more selected locations within an environment, the apparatus comprising:
- a) means for measuring incident gamma ray energy and count rate from one or more sources, for one or more viewed portions of the environment at one or more viewed portions within the environment, the apparatus obtaining a measured spectrum for one or more viewed portions from this incident gamma ray energy and count rate information;
- b) means for measuring the spatial position of said one or more viewed portions;
- c) calculating means for determining an emitted spectrum for each viewed portion of the environment from said measured spectrum for each said viewed portion of the environment;
- d) processing means adapted to receive inputs corresponding to the emitted spectra and the spatial position;
- and
- e) calculating means for determining the dose or dose rate at one or more selected locations from a total calculated gamma ray energy incident on those selected location arising from the emitted spectrum of the one or more sources, wherein the calculating means for determining an emitted spectrum divide the measured spectrum into a series of energy ranges or bins, sum the count rates or counts falling within a range or bin to give a total count rate or total count for that range or bin, the series of energy ranges or bins including a highest energy range or bin, the calculating means for determining an emitted spectrum analyzing by subtracting from the ranged or binned spectrum a value, the value being based on a response function multiplied by a variable factor to reduce the range or bin under analysis to zero.
A method for determining a radiation dose rate for a selected location within an environment, the method comprising:
- measuring incident gamma ray energy and count rate for one or more measured locations within the environment to obtain a measured spectrum for the measured locations;
- measuring the spatial position of the measured locations;
- determining an emitted spectrum for the measured locations based at least in part on the measured spectrum;
- determining the dose rate at at least one selected location that is distinct from the measured locations based at least in part on the emitted spectrum that has been determined for the measured locations;
- and
- wherein the measured spectra is divided into a series of energy ranges or bins, the count rates falling within each range or bin summed together to give a total count for each bin, the range or binned measured spectrum having a highest energy level bin, said highest energy level bin analyzed first by subtracting from the range or binned measured spectrum a value based on a response function multiplied by a variable factor to reduce the bin under analysis to zero, a highest remaining energy bin still contributing to the range or binned measured spectrum after subtraction is analyzed next, and wherein the analyzing process is sequentially repeated to reduce the ranged or binned spectrum to zero.
Dependencies are inferred from the claim text.