A radiation image conversion panel having a high luminance and sharpness is provided by growing columnar crystals from the root portion. The radiation image conversion panel includes a support; and a phosphor layer mainly composed of an alkali halide, the phosphor layer being formed by vapor deposition; wherein the phosphor layer includes a plurality of domains formed of a plurality of phosphor columnar crystals; each of the domains is a single phosphor columnar crystal or an aggregation of phosphor columnar crystals having substantially the same crystal orientation, and has an average diameter of 0.2 to 10 m; and the phosphor columnar crystals are crystalline from root portion at which crystal growth started.

A radiation detector includes a sensor panel having a light receiving surface, a first scintillator panel and a second scintillator panel disposed on the light receiving surface in a state of being adjacent to each other along the light receiving surface, and a moisture-proof layer. The first scintillator panel has a first substrate and a first scintillator layer including a plurality of columnar crystals. The second scintillator panel has a second substrate and a second scintillator layer including a plurality of columnar crystals. The first scintillator layer reaches at least a first portion of the first substrate. The second scintillator layer reaches at least a second portion of the second substrate. The moisture-proof layer is provided continuous over the first scintillator panel and the second scintillator panel.

Multi-component rare-earth garnet optical materials comprising at least three different rare-earth elements and an optional activator ion are described. The optical materials include rare-earth garnet scintillators. Methods of preparing powders, ceramics, and single crystals of the optical materials are also described. In addition, radiation detectors comprising the rare-earth garnet scintillators are described.

The present invention relates to a method for forming an optical waveguide sensor for detecting ions containing radioactive isotopes in an aqueous solution. The method comprises treating a substrate surface by cleaning the substrate surface with one or more solvents to enable coating with a crosslinking agent, the substrate being selected from silica or silicon substrate, coating the treated substrate surface with the crosslinking agent selected from carboxylic acid functional group containing organic molecules to form a crosslinked substrate surface, coating the crosslinked substrate surface with a scintillating agent, and coating the substrate surface with a ligand capable of reacting with a radioactive isotope in an aqueous solution to form a functionalized substrate surface. The present invention also relates to the optical waveguide sensor for detecting radioactive isotopes fabricated with the method of the present invention.