Fiber optic dosimeter system using electron trapping materials

Claim 1

A fiber optic dosimeter system, comprising: an optical fiber having first and second ends; a radiation-sensitive infrared stimulable phosphor coated onto the tip of the first end of said optical fiber, said phosphor comprising: a base material of substantially strontium sulfide, a first dopant of samarium, and a second dopant of selected from the group consisting of cerium oxide, cerium fluoride, cerium chloride, and cerium sulfide, said phosphor having a plurality of energy levels and having the capability to trap electrons in a trapping energy level when electrons attempt to return to a ground state after having been excited above said trapping energy level as a result of impingement of radiation upon said material; a stimulating source optically coupled to the second end of said optical fiber for providing infrared energy through said optical fiber to said phosphor to raise said trapped electrons to a higher energy level, from which said electrons recombine and fall back to said ground state, emitting visible light defined as optically stimulated luminescence, such that said phosphor acts as an upconverter with respect to said stimulating infrared energy; and a visible light sensor coupled to the second end of said optical fiber for detecting the portion of said optically stimulated luminescence which passes back through said optical fiber to said visible light sensor and for converting the detected optically stimulated luminescence to an electrical signal proportional to the amount of radiation impinging upon the phosphor.

Claim 13

A method of fiber optic dosimetry, comprising the steps of: (a) exposing a radiation-sensitive infrared stimulable phosphor on a tip of a first end of an optical fiber to radiation to be measured to raise electrons in the phosphor from a ground energy level to an elevated energy storage level, said phosphor comprising: a base material of substantially strontium sulfide, a first dopant of samarium, and a second dopant of selected from the group consisting of cerium oxide, cerium fluoride, cerium chloride, and cerium sulfide; (b) sending optical stimulation in the form of infrared energy through the optical fiber from a second end of said optical fiber to the phosphor to release trapped electrons from said elevated energy storage level, the released electrons emitting optically stimulated luminescence in the form of visible light upon falling to said ground energy level, such that said phosphor acts as an upconverter with respect to said infrared optical stimulation; and (c) measuring said optically stimulated luminescence at said second end of said optical fiber.

Claim 14

A method of fiber optic dosimetry, comprising the steps of: (a) exposing a radiation-sensitive infrared stimulable phosphor on a tip of a first end of an optical fiber to radiation to be measured to raise electrons in the phosphor from a ground energy level to an elevated energy storage level, said phosphor comprising: a base material of substantially strontium sulfide, a first dopant of samarium, and a second dopant of selected from the group consisting of cerium oxide, cerium fluoride, cerium chloride, and cerium sulfide; (b) sending optical stimulation in the form of infrared energy through the optical fiber from a second end of said optical fiber to the phosphor to release trapped electrons from said elevated energy storage level, the released electrons emitting optically stimulated luminescence in the form of visible light upon falling to said ground energy level, such that said phosphor acts as an upconverter with respect to said infrared optical stimulation; and (c) measuring said optically stimulated luminescence at said second end of said optical fiber.