Scintillation compound including a rare earth element in a tetravalent state
A scintillation compound can include a rare earth element that is in a divalent (RE 2+ ) or a tetravalent state (RE 4+ ). The scintillation compound can include another element to allow for better change balance. The other element may be a principal constituent of the scintillation compound or may be a dopant or a co-dopant. In an embodiment, a metal element in a trivalent state (M 3+ ) may be replaced by RE 4+ and a metal element in a divalent state (M 2+ ). In another embodiment, M 3+ may be replaced by RE 2+ and M 4+ . In a further embodiment, M 2+ may be replaced by a RE 3+ and a metal element in a monovalent state (M 1+ ). The metal element used for electronic charge balance may have a single valance state, rather than a plurality of valence states, to help reduce the likelihood that the valance state would change during formation of the scintillation compound.
1. A scintillation compound comprising a rare earth element in a tetravalent state at a concentration of at least approximately 10 ppm atomic of the scintillation compound and a dopant that includes a different element in a divalent state at a concentration of at least 5 ppm atomic of the scintillation compound, wherein the scintillation compound is not a rare earth silicate compound.
2. The scintillation compound of claim 1 , wherein the rare earth element in the tetravalent state is at a concentration of at least approximately 20 ppm atomic of the scintillation compound.
3. The scintillation compound of claim 1 , wherein the rare earth element in the tetravalent state is at a concentration no greater than approximately 5% atomic of the scintillation compound.
4. The scintillation compound of claim 1 , wherein the rare earth element is a particular rare earth element in the tetravalent state that is at least approximately 5% of the total content of the particular rare earth element within the scintillation compound.
5. The scintillation compound of claim 1 , wherein the rare earth element is a particular rare earth element in the tetravalent state that is no greater than 100% of the total content of the particular rare earth element within the scintillation compound.
6. The scintillation compound of claim 1 , wherein the dopant is at a concentration of at least approximately 11 ppm atomic of the scintillation compound.
7. The scintillation compound of claim 1 , wherein the dopant is at a concentration no greater than approximately 5% atomic of the scintillation compound.
8. The scintillation compound of claim 1 , wherein a ratio of the rare earth element in the tetravalent state to the dopant is at least approximately 1:90.
9. The scintillation compound of claim 1 , wherein a ratio of the rare earth element in the tetravalent state to the dopant is no greater than approximately 90:1.
10. The scintillation compound of claim 1 , wherein the dopant comprises a Group 2 element.
11. The scintillation compound of claim 1 , wherein the Group 2 element is Ca or Sr.
12. The scintillation compound of claim 1 , wherein the rare earth element comprises Ce 4+ , Pr 4+ , or Tb 4+ .
13. The scintillation compound of claim 1 , wherein the scintillation compound comprises a metal-boron-oxygen compound.
14. The scintillation compound of claim 1 , wherein the scintillation compound comprises a metal-aluminum-oxygen compound, wherein the metal is different from aluminum.
15. The scintillation compound of claim 1 , wherein the scintillation compound comprises a metal-oxygen-sulfur compound.
16. The scintillation compound of claim 1 , wherein the scintillation compound comprises a metal-oxygen-halogen compound.
17. The scintillation compound of claim 1 , wherein the scintillation compound is used within a radiation detection apparatus, a positron emission tomography scanner, a laser device, or an optical storage device.
18. A scintillation compound comprising a rare earth element in a tetravalent state at a concentration of at least approximately 10 ppm atomic of the scintillation compound, wherein the scintillation compound is not a rare earth silicate compound wherein the scintillation compound comprises a metal halide.
19. A scintillation compound comprising a rare earth element in a tetravalent state at a concentration of at least approximately 10 ppm atomic of the scintillation compound, wherein the scintillation compound comprises a metal-phosphorus-oxygen compound.