Beta-ray thickness gauge using a two energy level beta-ray source

Claim 2

A radiation source useful in measuring the thickness of film specimens having thicknesses in the range 0 - 750 mg/cm2, said source comprising: a support, a first container stationarily mounted to said support at a first physical position, a second container stationarily mounted to said support at a second physical position different from said first position, thereby rendering said containers fixed relative to each other at different physical positions, a relatively low energy beta-emitting first radioactive material useful in measuring film thicknesses in one portion of said range, said first material being located in said first container, a relatively high energy beta-emitting second radioactive material useful in measuring film thickness in the remaining portion of said range, said second material being located in said second container, and having different beta energy emission characteristics than said first material, said first and second containers including means for causing both said first and second materials to simultaneously irradiate along a common aligned path the same film specimen, the thickness of which is being measured, with a homogenous mixture of radiation from both said first and second differently positioned materials.

Claim 3

A radiation source for irradiating a specimen with a homogenous beam of different energy radiation emitted by different energy-emitting materials, comprising: a first container having a first window located proximate the specimen to be measured and a second window located opposite said first window, a second container stationarily mounted relative to said first container and having a third window aligned with said second window, an energy-emitting first radioactive material located in said second container for irradiating said specimen to be measured along a path including said first, second, and third windows, and an energy-emitting second radioactive material located in said first container for irradiating said specimen through said first window simultaneously with the irradiating of said specimen by said first material, said second material having different energy emission characteristics than said first material, said second material also having a relatively low mass per unit area to thereby prevent undue attenuation of radiation from said first material as it passes to said specimen along said path including said second window and said first window.

Claim 4

A radiation source for irradiating a specimen with a homogenous beam of different energy radiation emitted by different energy-emitting materials, comprising: a first container having a first window located proximate the specimen to be measured and a second window located opposite said first window, a second container stationarily mounted relative to said first container and having a third window aligned with said second window, an energy-emitting first radioactive material located in said second container for irradiating said specimen to be measured along a path including said first, second, and third windows, and an energy-emitting second radioactive material located in said first container for irradiating said specimen through said first window simultaneously with the irradiating of said specimen by said first material, said second material having different energy emission characteristics than said first material, said second material also having a relatively low mass per unit area to thereby prevent undue attenuation of radiation from said first material as it passes to said specimen along said path including said second window and said first window.

Claim 5

The source of claim 2 wherein said second material is in a gaseous state and said first container is gas-tight.

Claim 6

The source of claim 3 wherein said first material is in a solid state.

Claim 7

The source of claim 2 wherein said second material is gaseous state Krypton-85, and said first material is solid state Strontium-90.

Claim 10

The method of claim 6 wherein said irradiating step includes simultaneously irradiating said specimen with a homogenous beam of beta radiation from Krypton-85 and Strontium-90.

Claim 11

A sensitivity-variable method of measuring the thickness of film specimens having thicknesses varying over the range of 0 -750 mg/cm2, comprising the steps of: simultaneously irradiating along a common aligned path the specimen being measured with a homogenous mixture of (a) relatively low energy beta radiation emitted by a first beta-emitting radioactive material located at a first point in space and useful in measuring thicknesses in one portion of said range and (b) relatively high energy beta radiation emitted by a second beta-emitting radioactive material located at a second point in space different from said first point and useful in measuring thicknesseS in the remainder of said range, said materials having different beta energy emission characteristics, altering the millicurie ratio of said first and second beta-emitting materials to thereby vary the sensitivity of said measuring method, and detecting said homogenous mixture of radiation after it has interacted with said specimen with a detector responsive to a homogenous mixture of radiation from both said first and second differently positioned radioactive materials.

Claim 12

A sensitivity-variable method of measuring the thickness of film specimens having thicknesses varying over the range of 0 -750 mg/cm2, comprising the steps of: simultaneously irradiating along a common aligned path the specimen being measured with a homogenous mixture of (a) relatively low energy beta radiation emitted by a first beta-emitting radioactive material located at a first point in space and useful in measuring thicknesses in one portion of said range and (b) relatively high energy beta radiation emitted by a second beta-emitting radioactive material located at a second point in space different from said first point and useful in measuring thicknesseS in the remainder of said range, said materials having different beta energy emission characteristics, altering the millicurie ratio of said first and second beta-emitting materials to thereby vary the sensitivity of said measuring method, and detecting said homogenous mixture of radiation after it has interacted with said specimen with a detector responsive to a homogenous mixture of radiation from both said first and second differently positioned radioactive materials.

Claim 13

A radiation source useful in measuring the thickness of film specimens over an extended thickness range, said source comprising: a support, a first container stationarily mounted to said support at a first physical position, a second container stationarily mounted to said support at a second physical position different from said first position, thereby rendering said containers fixed relative to each other at different positions, a relatively low energy emitting first radioactive material useful in measuring film thicknesses in a relatively low thickness portion of said range, said first material being located in said first container, a relatively high energy emitting second radioactive material useful in measuring film thickness in the remaining portion of said range, said second material being located in said second container and having different energy emission characteristics than said first material, said first and second containers including means for causing both said first and second materials to simultaneously irradiate along a common aligned path the same portion of a film specimen, the thickness of which is being measured, with a homogenous mixture of radiation from both said first and second differently positioned materials.

Claim 14

A radiation source useful in measuring the thickness of film specimens over an extended thickness range, said source comprising: a support, a first container stationarily mounted to said support at a first physical position, a second container stationarily mounted to said support at a second physical position different from said first position, thereby rendering said containers fixed relative to each other at different positions, a relatively low energy emitting first radioactive material useful in measuring film thicknesses in a relatively low thickness portion of said range, said first material being located in said first container, a relatively high energy emitting second radioactive material useful in measuring film thickness in the remaining portion of said range, said second material being located in said second container and having different energy emission characteristics than said first material, said first and second containers including means for causing both said first and second materials to simultaneously irradiate along a common aligned path the same portion of a film specimen, the thickness of which is being measured, with a homogenous mixture of radiation from both said first and second differently positioned materials.

Claim 15

A composite radiation source for irradiating a specimen with a homogenous mixture of different energy radiation emitted by first and second radiation sources, said composite source comprising: structure defining a first container, said first container structure being permeable to radiation at a first point proximate the specimen to be measured and at a second point different from said first point, structure defining a second container, said second container structure being permeable to radiation at a third point and mounted relative to said first container to provide alignment of said third point and said second point, a first radiation source located within said second container structure for irradiating said specimen along a path including said first, second, and third points, a second radiation source located within said first container for irradiating said specimen along a path including said first point simultaneously with the irradiation of said specimen by said first source, said radiation emitted from said second container at said third point being different than the radiation emitted from said second source, said second source having a relatively low mass per unit area to thereby prevent undue attenuation of radiation emitted from said second container as it passes to said specimen along a path including said first and second points.

Claim 16

A composite radiation source for irradiating a specimen with a homogenous mixture of different energy radiation emitted by first and second radiation sources, said composite source comprising: structure defining a first container, said first container structure being permeable to radiation at a first point proximate the specimen to be measured and at a second point different from said first point, structure defining a second container, said second container structure being permeable to radiation at a third point and mounted relative to said first container to provide alignment of said third point and said second point, a first radiation source located within said second container structure for irradiating said specimen along a path including said first, second, and third points, a second radiation source located within said first container for irradiating said specimen along a path including said first point simultaneously with the irradiation of said specimen by said first source, said radiation emitted from said second container at said third point being different than the radiation emitted from said second source, said second source having a relatively low mass per unit area to thereby prevent undue attenuation of radiation emitted from said second container as it passes to said specimen along a path including said first and second points.