Use of codoping to modify the scintillation properties of inorganic scintillators doped with trivalent activators
AssigneesSiemens Medical Solutions USA, Inc., University of Tennessee Research Foundation
InventorsMerry Anna Koschan, Charles L. Melcher, Lars A. Erikkson, Harold E. Rothfuss
Life of this patent
Estimating the term…
Abstract
Crystals with improved scintillation and optical properties are achieved by codoping with a trivalent dopant and a divalent and/or a monovalent dopant. Embodiments include codoping LSO, YSO, GSO crystals and LYSO, LGSO, and LYGSO crystals. Embodiments also include codoped crystals with a controlled monovalent or divalent:trivalent dopant ratio of from about 1:1 for increased light yield to about 4:1 for faster decay time.
Claims15
A scintillation material, comprising a crystal consisting essentially of:
- T2xLu2(1-x-y-z)Y2yGd2zSiO5;
- and
- at least one divalent codopant,
- wherein T is a trivalent activator dopant selected from the group consisting of Pr, Eu, Er and Yb,
- 0<2x<0.2,
- 0≦2y≦2(1−x),
- 0≦2z≦2(1−x), and
- 0≦(y+z)≦(1−x),
- wherein the ratio (a):(b) of the divalent dopant concentration (a) to the trivalent activator dopant concentration (b) is about 1:1, to maximize light output.
A scintillator material comprising a ceramic comprising:
- T2xLu2(1-x-y-z)Y2yGd2zSiO5;
- and
- at least one monovalent and/or divalent codopant,
- wherein T comprises at least one trivalent activator dopant,
- 0<2x<0.2,
- 0≦2y≦2(1−x),
- 0≦2z≦2(1−x), and
- 0≦(y+z)≦≦(1−x).
A method comprising growing a crystal consisting essentially of:
- T2xLu2(1-x-y-z)Y2yGd2zSiO5;
- and
- at least one monovalent and/or divalent codopant,
- wherein T is a trivalent dopant selected from the group consisting of Pr, Eu, Er and Yb,
- 0<2x<0.2,
- 0≦2y≦2(1−x),
- 0≦2z≦2(1−x), and
- 0≦(y+z)≦(1−x),
- the method further comprising controlling the ratio (a):(b) of the divalent dopant concentration (a) to the trivalent activator dopant concentration (b) to about 1:1 when the codopant is divalent.
A scintillation material, comprising a crystal consisting essentially:
- T2xLu2(1-x-y-z)Y2yGd2zSiO5;
- and
- at least one divalent codopant,
- wherein T is a trivalent activator dopant selected from the group consisting of Pr, Eu, Er and Yb,
- 0<2x<0.2, and
- 0<2(y+z)≦2(1−x),
- wherein the ratio (a):(b) of the divalent dopant concentration (a) to the trivalent activator dopant concentration (b) is about 1:1, to maximize light output.
Dependencies are inferred from the claim text.