Abstract: The invention presents a method of radiation dosimetry and radiation field imaging. It utilizes luminescent material based on aluminum oxide doped with carbon and magnesium (Al2O3:C,Mg) and containing aggregate oxygen vacancy defects. Storage of dosimetric information is based on ionization of the crystal matrix, generation of free electrons and capture of electrons and holes by traps and color centers. An absorbed dose is determined by non-destructive readout of fluorescence from color centers induced by radiation. The preferred mode of measurements is to illuminate the Al2O3:C,Mg phosphor with a red laser (at 635 or 650 nm) and to measure the intensity of 750 nm fluorescence. Method allows for high temperature and environmental stability of dose information. The detector material is insensitive to room light before and after the irradiation and provides a fast data rate during scanning for imaging of radiation fields.

Abstract: The present invention provides methods and apparatuses for writing information to, reading information from, and erasing information on a luminescent data storage medium comprising Al2O3. The method includes writing and erasing of the information using photoionization via sequential two-photon absorption and non-destructive reading the information using fluorescent detection. The apparatuses for writing and reading the information incorporate confocal detection and spherical aberration correction for multilayer volumetric fluorescent data storage. The methods also allow multilevel recording and readout of information for increased storage capacity.

Abstract: There is provided a system and method for estimating radiation exposure in real time or in near-real time while a dosimeter is being irradiated. In the preferred arrangement, OSL will be used to calculate estimates of the radiation dose rate, preferably by using comparisons between illumination values measured during and after lighting the dosimeter with a laser light of a predetermined frequency. A first preferred embodiment utilizes quasi-equilibrium OSL intensity with periodic stimulation during continuous irradiation. Another preferred embodiment utilizes the amplitude of the transient OSL signal during periodic stimulation. Another preferred embodiment utilizes the difference between the OSL intensity at the end of one stimulation period and the beginning of the next. Finally, another preferred monitors the time constant for the return of the transient OSL signal to equilibrium, following either a change in dose rate or during a periodic optical stimulation.

Abstract: The present invention provides methods and apparatuses for writing information to, reading information from, and erasing information on a luminescent data storage medium comprising Al2O3. The method includes writing and erasing of the information using photoionization via sequential two-photon absorption and non-destructive reading the information using fluorescent detection. The apparatuses for writing and reading the information incorporate confocal detection and spherical aberration correction for multilayer volumetric fluorescent data storage. The methods also allow multilevel recording and readout of information for increased storage capacity.

Abstract: There is provided a system and method for estimating radiation exposure in real time or in near-real time while a dosimeter is being irradiated. In the preferred arrangement, OSL will be used to calculate estimates of the radiation dose rate, preferably by using comparisons between illumination values measured during and after lighting the dosimeter with a laser light of a predetermined frequency. A first preferred embodiment utilizes quasi-equilibrium OSL intensity with periodic stimulation during continuous irradiation. Another preferred embodiment utilizes the amplitude of the transient OSL signal during periodic stimulation. Another preferred embodiment utilizes the difference between the OSL intensity at the end of one stimulation period and the beginning of the next. Finally, another preferred monitors the time constant for the return of the transient OSL signal to equilibrium, following either a change in dose rate or during a periodic optical stimulation.

Abstract: The invention presents a method of radiation dosimetry and radiation field imaging. It utilizes luminescent material based on aluminum oxide doped with carbon and magnesium (Al2O3:C,Mg) and containing aggregate oxygen vacancy defects. Storage of dosimetric information is based on ionization of the crystal matrix, generation of free electrons and capture of electrons and holes by traps and color centers. An absorbed dose is determined by non-destructive readout of fluorescence from color centers induced by radiation. The preferred mode of measurements is to illuminate the Al2O3:C,Mg phosphor with a red laser (at 635 or 650 nm) and to measure the intensity of 750 nm fluorescence. Method allows for high temperature and environmental stability of dose information. The detector material is insensitive to room light before and after the irradiation and provides a fast data rate during scanning for imaging of radiation fields.

Abstract: The instant invention teaches a method of preparing a luminescent detecting material for use in UV dosimetry which utilizes phototransferred luminescence. The detecting material has a set of shallow dosimetry traps for trapping electronic charge carriers, which are thermally released upon heating to a first temperature, and a set of deep traps for trapping electronic charge carriers, which charge carriers are released upon heating to a second temperature. The detecting material is prepared by irradiating the detecting material to fill the shallow and deep traps with charge carriers, heating the material to release charge carriers from the shallow traps, and then cooling the material. When the detecting material is subsequently exposed to ultraviolet light a proportion of charge carriers will be released from the deep traps to be retrapped in the shallow traps, thereby allowing for the measurement of phototransferred luminescence by thermal or optical stimulation.

Abstract: This invention relates generally to luminescence techniques for imaging radiation fields and, more specifically, to the use of experimental and mathematical methods to distinguish between dynamic irradiation and static—or other abnormal radiation—exposure conditions for applications in personnel and environ mental radiation dosimetry, or related fields. In more particular, the instant invention provides a rapid and reliable method of detecting abnormal dosimeter exposure conditions over a wide dynamic range of radiation doses, while avoiding significant background interference and stimulation light leakage. Additionally, the preferred embodiment of the instant invention uses a pulsed and synchronized luminescence detection scheme.

Abstract: The optically stimulated luminescence generated from a luminescent material having a relatively long lifetime of luminescence is measured by using short pulses of laser light stimulation and detecting luminescence only between pulses of light stimulation and after a certain delay following the stimulation pulse.

Abstract: A bimodal method for determining an unknown absorbed dose of radiation. An irradiated material is illuminated with ultraviolet or visible light and the luminescence which is emitted from the material is detected. The illuminating light is pulsed, with pulse widths varying from 1 ns to 500 ms. The luminescence emission from dosimetric traps is monitored after a delay following the end of the illumination pulse. The integrated luminescence signal is related to the initial absorbed dose of radiation and thus may be used to calculate the unknown absorbed dose after calibration. In a first mode, the material is completely detrapped--that is, all the dosimetric traps are emptied by the illumination beam. In a second mode the number of illumination pulses, each being followed by the time delay and by periods during which the luminescence signal is detected, is selected such that only a portion of the radiation-induced luminescence from the material is extracted.