US4507562A
Expired / Lapsed
US
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Methods for rapidly stimulating luminescent phosphors and recovering information therefrom
Assignee: Keithley Instruments LLC
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Filing: 1983-02-28
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Granted: 1985-03-26
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Expires: 2003-02-28
Abstract
Abstract Disclosed is a method for rapidly stimulating luminescent phosphors using laser beams. The laser beam must strike the luminous phosphor with an intensity sufficient to cause rapid release of luminescent energy stored within the phosphor as a result of previous exposure to ionizing radiation. Emission of the luminescent energy can occur within very brief peiods of time, for example, less than 100 nanoseconds. The invention also includes a method for determining the amount of ionizing radiation to which a luminescent phosphor was exposed. Also disclosed is an apparatus for carrying out these methods.
Inventors
- 👤 Jean Gasiot
- 👤 Peter F. Braunlich
- 👤 Jean P. Fillard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:57
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/20; G01T1/2012; G01T1/2014; G01T1/02; G01T1/10; G01T1/105
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
80 words
A method for rapidly and optically stimulating luminescent phosphors to cause luminescent energy previously stored in the luminescent phosphors to be rapidly released, comprising: directing an intense beam of photons from a laser at the luminescent phosphor for a period of time less than one millisecond and with a photon flux density of at least 5×10 19 photons per second and per square millimeter; said beam of photons having a wavelength approximately equal to the stimulation wavelength for the phosphor.
Claim 2
Independent Claim
80 words
A method for rapidly and optically stimulating luminescent phosphors to cause luminescent energy previously stored in the luminescent phosphors to be rapidly released, comprising: directing an intense beam of photons from a laser at the luminescent phosphor for a period of time less than one millisecond and with a photon flux density of at least 5×10 19 photons per second and per square millimeter; said beam of photons having a wavelength approximately equal to the stimulation wavelength for the phosphor.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein the beam of photons from the laser is focused prior to striking the luminescent phosphor.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the beam of photons occurs in a pulse lasting less than 1 microsecond.
Claim 5
Dependent Claim
26 words
The method of claim 1 wherein the beam of photons strikes a particular area of the luminescent phosphor for a period of less than 1 microsecond.
Claim 6
Dependent Claim
39 words
The method of claim 1 wherein the beam of photons strikes a particular area of the luminescent phosphor for a period of approximately 100 nanoseconds measured according to full width at half the maximum value of the beam intensity.
Claim 7
Dependent Claim
19 words
The method of claim 1 wherein the wavelength of the beam of photons is between 0.1 and 10 micrometers.
Claim 8
Dependent Claim
17 words
The method of claim 1 wherein the wavelength of the beam of photons is approximately 1.06 micrometers.
Claim 9
Dependent Claim
26 words
The method of claim 1 wherein the wavelength of the photon beam is approximately equal to the wavelength of a stimulation spectrum of the luminescent phosphor.
Claim 10
Dependent Claim
28 words
The method of claim 1 wherein the luminescent phosphors are from the group including calcium sulfide, strontium sulfide, magnesium sulfide or barium sulfide doped with europium and samarium.
Claim 11
Dependent Claim
21 words
The method of claim 1 wherein the luminescent phosphors are from the group including barium sulfide doped with cerium and samarium.
Claim 12
Dependent Claim
49 words
The method of claim 1 wherein: the beam of photons strikes the luminescent phosphor with a flux density of between 5×10 19 and 10 21 photons per second and per square millimeter; and the beam of photons strikes the luminescent phosphor for a period of less than 1 microsecond.
Claim 13
Dependent Claim
21 words
The method of claim 11 wherein the beam of photons has a wavelength in the range between 0.8 and 10 micrometers.
Claim 14
Dependent Claim
27 words
The method of claim 11 wherein the laser is a neodymium yttrium aluminum garnet laser producing a beam of photons having a wavelength of approximately 1.06 micrometers.
Claim 15
Dependent Claim
35 words
The method of claim 11 wherein the laser is a dye laser having a photon beam output which is adjustable over a range of wavelengths so that a variety of luminescent phosphors can be excited.
Claim 16
Dependent Claim
12 words
The method of claim 1 wherein the luminescent phosphor is barium fluoro-chloride.
Claim 17
Independent Claim
156 words
A method for determining the amount of ionizing radiation which has impinged upon a unit of luminescent phosphor, comprising: striking the unit of luminescent phosphor with a stimulating beam of photons from a laser; said stimulating beam of photons being emitted from the laser at a wavelength approximately equal to a stimulation wavelength of the phosphor for a period of time equal to less than 1 microsecond and at a photon flux density of at least 5×10 19 photons per second and per square millimeter; measuring the peak intensity of the luminescent emission beam produced by the unit of luminescent phosphor as a result of the previous step; correlating the measured peak intensity of the luminescent emission with experimentally derived standard values associated with the phosphor being used which relate phosphor emission beam peak intensity to the amount of ionizing radiation to determine the amount of ionizing radiation which impinged upon the unit of luminescent phosphor.
Claim 18
Independent Claim
156 words
A method for determining the amount of ionizing radiation which has impinged upon a unit of luminescent phosphor, comprising: striking the unit of luminescent phosphor with a stimulating beam of photons from a laser; said stimulating beam of photons being emitted from the laser at a wavelength approximately equal to a stimulation wavelength of the phosphor for a period of time equal to less than 1 microsecond and at a photon flux density of at least 5×10 19 photons per second and per square millimeter; measuring the peak intensity of the luminescent emission beam produced by the unit of luminescent phosphor as a result of the previous step; correlating the measured peak intensity of the luminescent emission with experimentally derived standard values associated with the phosphor being used which relate phosphor emission beam peak intensity to the amount of ionizing radiation to determine the amount of ionizing radiation which impinged upon the unit of luminescent phosphor.
Claim 19
Independent Claim
172 words
A method for determining the amount of ionizing radiation which has impinged upon a unit of luminescent phosphor, comprising: striking the unit of luminescent phosphor with a stimulating beam of photons from a laser; said stimulating beam of photons being emitted from the laser at a wavelength approximately equal to a stimulation wavelength of the phosphor for a period of time equal to less than 1 microsecond and at a photon flux density of at least 5×10 19 photons per second and per square millimeter; measuring the intensity of the luminescent emission beam produced by the unit of luminescent phosphor as a result of the previous step and integrating this value over time to produce a measurement of the total quantity of luminescent emission; comparing said measurement of the total quantity of luminescent emission with experimentally derived standard values associated with the phosphor being used which relate total quantity of luminescent emission to amount of ionizing radiation to determine the amount of ionizing radiation which impinged upon the unit of luminescent phosphor.
Claim 20
Independent Claim
172 words
A method for determining the amount of ionizing radiation which has impinged upon a unit of luminescent phosphor, comprising: striking the unit of luminescent phosphor with a stimulating beam of photons from a laser; said stimulating beam of photons being emitted from the laser at a wavelength approximately equal to a stimulation wavelength of the phosphor for a period of time equal to less than 1 microsecond and at a photon flux density of at least 5×10 19 photons per second and per square millimeter; measuring the intensity of the luminescent emission beam produced by the unit of luminescent phosphor as a result of the previous step and integrating this value over time to produce a measurement of the total quantity of luminescent emission; comparing said measurement of the total quantity of luminescent emission with experimentally derived standard values associated with the phosphor being used which relate total quantity of luminescent emission to amount of ionizing radiation to determine the amount of ionizing radiation which impinged upon the unit of luminescent phosphor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-25 | 1988-09-24 | 1989-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-25 | 1992-09-24 | 1993-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-25 | 1996-09-24 | 1997-03-26 | $7700.00 | Window Closed / Lapsed |