Scintillator having a phase separation structure and radiation detector using the same

A scintillator, comprising:

• a first crystal phase including multiple columnar crystals;
• and
• a second crystal phase covering a side of each of the multiple columnar crystals,
• wherein the scintillator has a first surface and a second surface, which are not located on the same plane,
• wherein each of the first surface and the second surface has a portion to which the second crystal phase is exposed,
• wherein the first crystal phase comprises a perovskite type oxide material including at least one element selected from the group consisting of Lu and Gd, and a rare earth element as an emission center,
• wherein the first crystal phase emits light by radiation excitation, and
• wherein a material constituting the first crystal phase and a material constituting the second crystal phase are capable of forming together a phase separation structure during solidification.

A scintillator, comprising:

• a first crystal phase including multiple columnar crystals;
• and
• a second crystal phase covering a side of each of the multiple columnar crystals,
• wherein the first crystal phase comprises a perovskite type oxide material including at least one element selected from the group consisting of Lu and Gd, and an emission center,
• wherein the first crystal phase emits light by radiation excitation,
• wherein the second crystal phase comprises a garnet type oxide material represented by A3B5O12, including A and B, where A is at least one element selected from the group consisting of Lu and Gd, and B is at least one element selected from the group consisting of Al, Sc, and Y, and
• wherein 0.001 mol% or more of a rare earth element comprising at least one of Ce3+, Tb3+, Pr3+, and Eu3+ with respect to a total amount of a substance of the first crystal phase and the second crystal phase is contained as the emission center.