摘要:
LSO scintillation crystals with improved scintillation and optical properties are achieved by controlled co-doping a LSO crystal melt with amounts of cerium and an additional codopant such as calcium or other divalent cations. Crystal growth atmosphere is optimized by controlling the amount of oxygen in the atmosphere. Zinc is added as an additional material to restabilize crystal growth where calcium co-dopant is added. The decay time of the scintillation crystal can be controlled by controlling the concentration of co-dopant added.
摘要:
A Czochralski (“CZ”) single-crystal growth process system continuously grows crystal boules in a chamber furnace during a single thermal cycle. Finished boules are transferred from the furnace chamber, without need to cool the furnace, to an adjoining cooling chamber for controlled cooling. Controlled cooling is preferably accomplished by transporting boules along a path having an incrementally decreasing temperature. In order to maximize crystal boule yield in a single furnace thermal cycle, the crucible assembly may be recharged with crystal growth aggregate and/or slag may be discharged during the crystal boule growth process without opening the furnace.
摘要:
A Czochralski process (“CZ”) crystal growth method and furnace having a heater capable of generating a heating zone, a crucible within the heating zone and capable of retaining a volume of molten crystal growth material forming a melt line oriented in a designated position within the heating zone, a seed growth rod retractable from the crucible with a rod retraction mechanism, for forming a crystal boule thereon proximal the melt line from the molten crystal growth material. The furnace causes relative movement between the crucible and heating zone as the crystal boule is retracted, so that the melt line is maintained in the designated position within the heating zone. In some embodiments relative movement is based at least in part on sensed weight of the growing crystal boule. In other embodiments the crucible growth rod retraction mechanism are fixed relative to each other by a gantry.
摘要:
The present disclosure discloses, in one arrangement, a single crystalline iodide scintillator material having a composition of the formula AM1-xEuxI3, A3M1-xEuxI5 and AM2(1-x)Eu2xI5, wherein A consists essentially of any alkali metal element (such as Li, Na K, Rb, Cs) or any combination thereof, M consists essentially of Sr, Ca, Ba or any combination thereof, and 0≦x≦1. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the iodide scintillator materials include radiation detectors and their use in medical and security imaging.
摘要:
A method of making LSO scintillators with high light yield and short decay times is disclosed. In one arrangement, the method includes codoping LSO with cerium and another dopant from the IIA or IIB group of the periodic table of elements. The doping levels are chosen to tune the decay time of scintillation pulse within a broader range (between about ˜30 ns up to about ˜50 ns) than reported in the literature, with improved light yield and uniformity. In another arrangement, relative concentrations of dopants are chosen to achieve the desired light yield and decay time while ensuring crystal growth stability.
摘要:
The present disclosure discloses, in one arrangement, a single crystalline chloride scintillator material having a composition of the formula A3MCl6, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. In another arrangement, a chloride scintillator material is single-crystalline and has a composition of the formula AM2Cl7, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Specific examples of these scintillator materials include single-crystalline Cs3CeCl6, CsCe2Cl7, Ce-doped KGd2Cl7 (KGd2(1-x)Ce2xCl7) and Ce-doped CsGd2Cl7 (CsGd2(1-x)Ce2xCl7). In a further arrangement, the Bridgman method can be used to grown single crystals of the chloride scintillator materials compounds synthesized from starting chlorides.
摘要:
A halide scintillator material is disclosed. The material is single-crystalline and has a composition of the formula A3MBr6(1-x)Cl6x (such as Cs3CeBr6(1-x)Cl6x) or AM2Br7(1-x)Cl7x (such as CsCe2Br7(1-x)Cl7x), 0≦x≦1, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Furthermore, a method of making halide scintillator materials of the above-mentioned compositions is disclosed. In one example, high-purity starting halides (such as CsBr, CeBr3, CsCl and CeCl3) are mixed and melted to synthesize a compound of the desired composition of the scintillator material. A single crystal of the scintillator material is then grown from the synthesized compound by the Bridgman method. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.
摘要:
A halide scintillator material is disclosed. The material is single-crystalline and has a composition of the formula A3MBr6(1-x)Cl6x (such as Cs3CeBr6(1-x)Cl6x) or AM2Br7(1-x)Cl7x (such as CsCe2Br7(1-x)Cl7x), 0≦x≦1, wherein A consists essentially of Li, Na K, Rb, Cs or any combination thereof, and M consists essentially of Ce, Sc, Y, La, Lu, Gd, Pr, Tb, Yb, Nd or any combination thereof. Furthermore, a method of making halide scintillator materials of the above-mentioned compositions is disclosed. In one example, high-purity starting halides (such as CsBr, CeBr3, CsCl and CeCl3) are mixed and melted to synthesize a compound of the desired composition of the scintillator material. A single crystal of the scintillator material is then grown from the synthesized compound by the Bridgman method. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.
摘要:
Apparatuses, computer-readable mediums, and methods are provided. In one embodiment, a positron emission tomography (“PET”) detector array is provided which includes a plurality of crystal elements arranged in a two-dimensional checkerboard configuration. In addition, there are empty spaces in the checkerboard configuration. In various embodiments, the empty spaces are filled with passive shielding, transmission source assemblies, biopsy instruments, surgical instruments, and/or electromagnetic sensors. In various embodiments, the crystal elements and the transmission source assemblies simultaneously perform emission/transmission acquisitions.
摘要:
A Czochralski process (“CZ”) crystal growth method and furnace having a heater capable of generating a heating zone, a crucible within the heating zone and capable of retaining a volume of molten crystal growth material forming a melt line oriented in a designated position within the heating zone, a seed growth rod retractable from the crucible with a rod retraction mechanism, for forming a crystal boule thereon proximal the melt line from the molten crystal growth material. The furnace causes relative movement between the crucible and heating zone as the crystal boule is retracted, so that the melt line is maintained in the designated position within the heating zone. In some embodiments relative movement is based at least in part on sensed weight of the growing crystal boule. In other embodiments the crucible growth rod retraction mechanism are fixed relative to each other by a gantry.