Non-destructive method for determining neutron exposure and constituent concentrations of a body

Claim 2

A portable, non-destructive method for determination of the spatial distribution of neutron exposure to which a selected object has been subjected, comprising the following steps: exposing the shielded detector of a spectrometer to a limited portion of a surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a traverse of the surface area by the shielded detector; recording a flux density peak value of the gamma-rays at a selected energy level characteristic of neutron exposure; identifying a relationship between the flux density peak value and the spatial activity density for the measured gamma-rays; and subsequently deriving spatial and angular information concering neutron exposure across the surface area of the object by known relationships to the identified spatial activity density value.

Claim 3

A method as set out in claim 1, wherein the spatial activity density value is related to a neutron attenuation coefficient value measured by an independent measurement technique.

Claim 4

A method as set out in claim 1, wherein a second measurement of detected gamma-rays is utilized to identify the desired relationship between the flux density peak value and the spatial activity density value for the measured gamma-rays.

Claim 5

A portable non-destructive method for determination of the neutron exposure to which a selected surface area on a object has been subjected, comprising the following steps: exposing the solid state lithium-drifted silicon detector of a Compton Recoil Gamma-Ray Spectrometer to a limited portion of the surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a first traverse of the surface area by the shielded detector; recording a first flux density peak value of the gamma-rays at a selected energy level characteristic of neutron exposure; identifying a first relationship between the first flux density peak value and the spatial activity density value for the measured gamma-rays; modifying the exposure of the detector to the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a second traverse of the surface area by the detector; recording a second flux density peak value of the gamma-rays at the previously selected energy level; identifying a second relationship between the second flux density peak value and the spatial activity density value; solving the first and second relationships to identify the spatial activity density value of the gamma-rays at the characteristic energy level; and subsequently deriving information concerning spatial and angular neutron exposure of the object by known relationships to the identified spatial activity density value.

Claim 6

A portable non-destructive method for determination of the neutron exposure to which a selected surface area on a object has been subjected, comprising the following steps: exposing the solid state lithium-drifted silicon detector of a Compton Recoil Gamma-Ray Spectrometer to a limited portion of the surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a first traverse of the surface area by the shielded detector; recording a first flux density peak value of the gamma-rays at a selected energy level characteristic of neutron exposure; identifying a first relationship between the first flux density peak value and the spatial activity density value for the measured gamma-rays; modifying the exposure of the detector to the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a second traverse of the surface area by the detector; recording a second flux density peak value of the gamma-rays at the previously selected energy level; identifying a second relationship between the second flux density peak value and the spatial activity density value; solving the first and second relationships to identify the spatial activity density value of the gamma-rays at the characteristic energy level; and subsequently deriving information concerning spatial and angular neutron exposure of the object by known relationships to the identified spatial activity density value.

Claim 7

A portable, non-destructive method for determining constituent concentrations of a selected irradiated object comprising the following steps: exposing the detector of a spectrometer to a limited portion of the surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a traverse of the surface area by the shielded detector; recording a flux density peak value of the gamma-rays at a selected energy level characteristic of neutron exposure; identifying a relationship between the flux density peak value and the spatial activity density for the measured gamma-rays; and subsequently deriving information concerning the spatial constituant concentrations across the surface area of the object by known relationships to the identified spatial activity density value.

Claim 8

A portable, non-destructive method for determining constituent concentrations of a selected irradiated object comprising the following steps: exposing the detector of a spectrometer to a limited portion of the surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a traverse of the surface area by the shielded detector; recording a flux density peak value of the gamma-rays at a selected energy level characteristic of neutron exposure; identifying a relationship between the flux density peak value and the spatial activity density for the measured gamma-rays; and subsequently deriving information concerning the spatial constituant concentrations across the surface area of the object by known relationships to the identified spatial activity density value.

Claim 9

A method as set out in claim 5, including taking a sequential series of measurements over a given time period.

Claim 10

A method as set out in claim 5, wherein the flux density peak value of the gamma-rays from a specific constituent is identified to determine the concentration of said specific constituent in said object by known deductive relationships.

Claim 11

A method as set out in claim 7, wherein said specific constituent is copper.

Claim 12

A method as set out in claim 6, wherein said series of measurements are taken with one detector and collimator arrangement.

Claim 13

A method as set out in claim 6, wherein said series of measurements are taken with a plurality of detector and collimator arrangements.