Patent Number: 
Section: claims

1. A scintillator panel comprising on a support a base layer and a phosphor layer provided sequentially in this order, wherein the phosphor layer comprises columnar phosphor crystals formed of a phosphor parent compound and an activator by a process of vapor phase deposition and the base layer comprises crystals formed of the phosphor parent compound and the activator, and a relative density of the base layer is lower than a relative density of the phosphor layer and a relative content of the activator of the base layer is lower than a relative content of the activator of the phosphor layer, provided that the relative content of the activator of the base layer is 0.1 to 0.7 mole % and the relative content of the activator of the phosphor layer is 0.1 to 5 mole %. 2. The scintillator panel, as claimed in claim 1, wherein a thickness of the base layer satisfies the following expression:Expression 0.01<[(thickness of base layer)/(thickness of phosphor layer)]<0.5. 3. The scintillator panel, as claimed in claim 1, wherein the base layer is a layer comprising crystals formed by a process of vapor phase deposition. 4. The scintillator panel, as claimed in claim 1, wherein the phosphor parent compound is cesium iodide (CsI) and the activator is thallium (Tl). 5. A method of preparing a scintillator panel comprising on a support a base layer and a phosphor layer, the method comprising:depositing a phosphor parent compound and an activator on the base layer by a process of vapor phase deposition to form the phosphor layer comprised of columnar phosphor crystals,wherein the base layer comprises crystals comprised of the phosphor parent compound and the activator, and a relative density of the base layer is lower than a relative density of the phosphor layer and a relative content of the activator of the base layer is lower than a relative content of the activator of the phosphor layer, provided that the relative content of the activator of the base layer is 0.1 to 0.7 mole % and the relative content of the activator of the phosphor layer is 0.1 to 5 mole %. 6. The method, as claimed in claim 5, wherein a thickness of the base layer satisfies the following expression:Expression 0.01<[(thickness of base layer)/(thickness of phosphor layer)]<0.5. 7. The method, as claimed in claim 5, wherein the base layer is a layer comprising crystals formed by a process of vapor phase deposition. 8. The method, as claimed in claim 5, wherein the phosphor parent compound is cesium iodide (CsI) and the activator is thallium (Tl).