Wide-range radiation gage for determining deviation of a material property with a controlled-gain detector in an interruptable self-balancing measuring loop

Claim 2

In a material measuring system which converts radiation into a light source as a function of a material property, wide-range photoelectric gaging apparatus for determining deviation of a material property from a nominal value, comprising: a. an interruptable self-balancing measuring loop comprising: (.1) a variable-gain photodetector receiving said light source, (.2) deviation measuring circuit means operative in response to photodetector output for producing an error signal related to said material property, and (.3) switched automatic balancing circuit means for varying photodetector gain in response to said error signal, thereby reducing the error signal and balancing the measuring loop at a null point anywhere in a wide range of gage operation, said balancing circuit means adapted to be disabled and maintain photodetector gain at a fixed value in response to material presence pulse, b. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, c. means responsive to standards presence and material movement into said gage for producing said material presence pulse, thereby interrupting the self-balancing measuring loop at said nominal material value and thereafter causing said material standards to be removed from said radiation, and d. utilization means responsive to said error signal for determining the amount of deviation of said material property from said nominal value thereof.

Claim 3

In a material measuring system which converts radiation into a light source as a function of a material property, wide-range photoelectric gaging apparatus for determining deviation of a material property from a nominal value, comprising: a. a controlled-gain photodetector for producing a variable detector signal in response to variations in said light source and a gain controlling energizing signal, b. measuring circuit means including comparator means responsive to the difference between said detector signal and a comparator reference signal for producing an error signal, c. switched integrator circuit means for integrating said error signal and producing an integrated error signal which is related to a nominal value of said material property being gaged, said integrator circuit adapted to be disabled and maintain its output in response to a material presence pulse, d. a variable source of gain-controlling energizing signal responsive to the integrated error signal for varying photodetector gain to maintain said error signal at a virtually zero value, e. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, f. means for generating said material presence pulse in response to standards presence and a leading edge of said material entering the gaging apparatus, said pulse disabling said integrator and maintaining said energizing voltage and said photodetector gain at a constant value corresponding to the nominal value of said material property, and thereafter said material presence pulse causing said material standards means to be removed from said radiation, and g. utilization means responsive to the error signal to determine the amount of deviation of said material property from a nominal value thereof.

Claim 4

In a material measuring system which converts radiation into a light source as a function of a material property, wide-range photoelectric gaging apparatus for determining deviation of a material property from a nominal value, comprising: a. a controlled-gain photodetector for producing a variable detector signal in response to variations in said light source and a gain controlling energizing signal, b. measuring circuit means including comparator means responsive to the difference between said detector signal and a comparator reference signal for producing an error signal, c. switched integrator circuit means for integrating said error signal and producing an integrated error signal which is related to a nominal value of said material property being gaged, said integrator circuit adapted to be disabled and maintain its output in response to a material presence pulse, d. a variable source of gain-controlling energizing signal responsive to the integrated error signal for varying photodetector gain to maintain said error signal at a virtually zero value, e. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, f. means for generating said material presence pulse in response to standards presence and a leading edge of said material entering the gaging apparatus, said pulse disabling said integrator and maintaining said energizing voltage and said photodetector gain at a constant value corresponding to the nominal value of said material property, and thereafter said material presence pulse causing said material standards means to be removed from said radiation, and g. utilization means responsive to the error signal to determine the amount of deviation of said material property from a nominal value thereof.

Claim 5

In a material measuring systeM which converts radiation into a nonlinear light source as a function of a material property, wide-range photoelectric gaging apparatus for determining deviation of a material property from a nominal value, comprising: a. a controlled-gain photodetector for producing a variable detector signal in response to variations in said nonlinear light source and a gain controlling energizing signal, said photodetector gain varying nonlinearly with said material property, b. measuring circuit means including linearizer means for performing a predetermined correction of said detector signal and further including comparator means responsive to the linearized detector signal and a comparator reference signal for producing an error signal having a predetermined correction, c. switched integrator circuit means for integrating said corrected error signal and producing an integrated error signal having a nonlinear relationship to a nominal value of the material property being gaged, said integrator circuit adapted to be disabled and maintain its output in response to a material presence pulse, d. a variable source of gain-controlling energizing signal responsive to the integrated, corrected, error signal for varying photodetector gain to maintain said error signal at a virtually zero value, e. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, f. means for generating said material presence pulse in response to standards presence and a leading edge of said material entering the gaging apparatus, said pulse disabling said integrator and maintaining said energizing voltage and said photodetector gain at a constant value corresponding to said nominal property, and thereafter said material presence pulse causing said material standards means to be removed from said radiation, g. deviation gain adjusting circuit means for processing said corrected error signal and said integrated corrected error signal to produce a constant-gain linear deviation signal, and h. utilization means responsive to said linear deviation signal to determine the amount of deviation of said material property from said nominal value thereof.

Claim 6

In a material measuring systeM which converts radiation into a nonlinear light source as a function of a material property, wide-range photoelectric gaging apparatus for determining deviation of a material property from a nominal value, comprising: a. a controlled-gain photodetector for producing a variable detector signal in response to variations in said nonlinear light source and a gain controlling energizing signal, said photodetector gain varying nonlinearly with said material property, b. measuring circuit means including linearizer means for performing a predetermined correction of said detector signal and further including comparator means responsive to the linearized detector signal and a comparator reference signal for producing an error signal having a predetermined correction, c. switched integrator circuit means for integrating said corrected error signal and producing an integrated error signal having a nonlinear relationship to a nominal value of the material property being gaged, said integrator circuit adapted to be disabled and maintain its output in response to a material presence pulse, d. a variable source of gain-controlling energizing signal responsive to the integrated, corrected, error signal for varying photodetector gain to maintain said error signal at a virtually zero value, e. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, f. means for generating said material presence pulse in response to standards presence and a leading edge of said material entering the gaging apparatus, said pulse disabling said integrator and maintaining said energizing voltage and said photodetector gain at a constant value corresponding to said nominal property, and thereafter said material presence pulse causing said material standards means to be removed from said radiation, g. deviation gain adjusting circuit means for processing said corrected error signal and said integrated corrected error signal to produce a constant-gain linear deviation signal, and h. utilization means responsive to said linear deviation signal to determine the amount of deviation of said material property from said nominal value thereof.

Claim 7

A wide-range radiation gage for determining deviation of a material property from a nominal value, comprising: a. means including a source of radiation and a scintillator for producing a light source which varies as a function of said material property, b. an interruptable self-balancing measuring loop comprising (.1) a variable-gain photodetector receiving said light source, (.2) deviation measuring circuit means operative in response to photodetector output for producing an error signal related to said material property, and (.3) switched automatic balancing circuit means for varying photodetector gain in response to said error signal, thereby reducing the error signal and balancing the measuring loop at a null point anywhere in a wide range of gage operation, said balancing circuit means adapted to be disabled and maintain photodetector gain at a fixed value in response to material presence pulse, b. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, c. means responsive to standards presence and material movement into said gage for producing said material presence pulse, thereby interrupting the self-balancing measuring loop at said nominal material value and thereafter causing said material standards to be removed from said radiation, and d. utilization means responsive to said error signal for determining the amount of deviation of said material property from said nominal value thereof.

Claim 8

A wide-range radiation gage for determining deviation of a material property from a nominal value, comprising: a. means including a source of radiation and a scintillator for producing a light source which varies as a function of said material property, b. an interruptable self-balancing measuring loop comprising (.1) a variable-gain photodetector receiving said light source, (.2) deviation measuring circuit means operative in response to photodetector output for producing an error signal related to said material property, and (.3) switched automatic balancing circuit means for varying photodetector gain in response to said error signal, thereby reducing the error signal and balancing the measuring loop at a null point anywhere in a wide range of gage operation, said balancing circuit means adapted to be disabled and maintain photodetector gain at a fixed value in response to material presence pulse, b. material standards means introduced into the radiation prior to material gaging for causing said measuring loop to zero said error signal and establish photodetector gain at a null point corresponding to a nominal value of material to be gaged, c. means responsive to standards presence and material movement into said gage for producing said material presence pulse, thereby interrupting the self-balancing measuring loop at said nominal material value and thereafter causing said material standards to be removed from said radiation, and d. utilization means responsive to said error signal for determining the amount of deviation of said material property from said nominal value thereof.

Claim 9

The apparatus of claIm 4 wherein said source of radiation is constant average potential X-ray source.

Claim 10

The apparatus of claim 4 wherein said source of radiation is a pulsed average potential X-ray source and the deviation circuit means includes a sample-and-hold circuit triggered in response to the pulsing of said X-ray source for sampling and holding of the peaks of pulsed photodetector signals.

Claim 11

The apparatus of claim 4 wherein said source of radiation is a nuclear radiation source, preferably monoenergetic.

Claim 12

The apparatus of claim 4 wherein said material standards means includes digital mechanical standards adapted to be interposed in a path between said radiation source and said scintillator in response to preselection signals, said standards means further adapted to be removed from said path in response to said means (d).

Claim 13

The apparatus of claim 4 wherein said means (d) is adapted to act in response to detecting the leading edge of the gaged material when entering the radiation gage.