The invention relates to an inorganic scintillator material of formula Lu.sub.(2-y)Y.sub.(y-z-x)Ce.sub.xM.sub.zSi.sub.(1-v)M.sub.vO.sub.5, in which: M represents a divalent alkaline earth metal and M represents a trivalent metal, (z+v) being greater than or equal to 0.0001 and less than or equal to 0.2; z being greater than or equal to 0 and less than or equal to 0.2; v being greater than or equal to 0 and less than or equal to 0.2; x being greater than or equal to 0.0001 and less than 0.1; and y ranging from (x+z) to 1. In particular, this material may equip scintillation detectors for applications in industry, for the medical field (scanners) and/or for detection in oil drilling. The presence of Ca in the crystal reduces the afterglow, while stopping power for high-energy radiation remains high.

A scintillation crystal can include a rare earth silicate, an activator, and a Group 2 co-dopant. In an embodiment, the Group 2 co-dopant concentration may not exceed 200 ppm atomic in the crystal or 0.25 at % in the melt before the crystal is formed. The ratio of the Group 2 concentration/activator atomic concentration can be in a range of 0.4 to 2.5. In another embodiment, the scintillation crystal may have a decay time no greater than 40 ns, and in another embodiment, have the same or higher light output than another crystal having the same composition except without the Group 2 co-dopant. In a further embodiment, a boule can be grown to a diameter of at least 75 mm and have no spiral or very low spiral and no cracks. The scintillation crystal can be used in a radiation detection apparatus and be coupled to a photosensor.

Plastic products containing at least one synthetic material and at least one luminophore of general formula (I) A.sub.1?x?y?zB*.sub.yB.sub.2SiO.sub.4:Ln.sup.1.sub.xLn.sup.2.sub.z can be produced. A is selected from the group of Mg, Ca, Sr and Ba; B is selected from the group of Li, Na, K, Rb and Cs; B* is selected from among the group of Li, Na and K; and B=B* or B?B*, preferably B?B*. Ln.sup.1 is selected from among the group consisting of praseodymium (Pr), erbium (Er) and neodymium (Nd); Ln.sup.2 is gadolinium (Gd); x=0.0001 to 0.0500; z=0.0000 or z=0.0001 to 0.3000, with the proviso that y=x+z. Objects that are made of the plastic products can be produced.

A preparation method and use of a green fluorescent transparent ceramic are disclosed. The preparation method includes: weighing, according to a stoichiometric ratio, elements present in Ca.sub.3-x-yCe.sub.xA.sub.ySc.sub.2-xB.sub.zSi.sub.3-mC.sub.mO.sub.12, in forms of oxides, carbonates or nitrates as raw materials; mixing the raw materials, annealing, melting at a high temperature, cooling and annealing at a low temperature; putting the glass into a high-temperature furnace, holding, raising the temperature, and performing crystallization and densification sintering; finally cutting, reducing and surface-polishing, where A is at least one from the group consisting of Lu, Y, Gd, La and Na; B is at least one from the group consisting of Zr, Hf and Mg; C is at least one from the group consisting of Al and P; x, y, z and m satisfy 0.001?x?0.06, 0?y?0.06, 0?z?0.06 and 0?m?0.3, respectively.

The invention relates to an inorganic scintillator material of formula Lu.sub.(2-y)Y.sub.(y-z-x) Ce.sub.xM.sub.zSi.sub.(1-v)M.sub.vO.sub.5, in which: M represents a divalent alkaline earth metal and M represents a trivalent metal, (z+v) being greater than or equal to 0.0001 and less than or equal to 0.2; z being greater than or equal to 0 and less than or equal to 0.2; v being greater than or equal to 0 and less than or equal to 0.2; x being greater than or equal to 0.0001 and less than 0.1; and y ranging from (x+z) to 1.

In particular, this material may equip scintillation detectors for applications in industry, for the medical field (scanners) and/or for detection in oil drilling. The presence of Ca in the crystal reduces the afterglow, while stopping power for high-energy radiation remains high.

A method of growing a rare-earth oxyorthosilicate crystal, and crystals grown using the method are disclosed. The method includes preparing a melt by melting a first substance including at least one first rare-earth element and providing an atmosphere that includes an inert gas and a gas including oxygen.

A scintillation crystal can include a rare earth silicate, an activator, and a Group 2 co-dopant. In an embodiment, the Group 2 co-dopant concentration may not exceed 200 ppm atomic in the crystal or 0.25 at % in the melt before the crystal is formed. The ratio of the Group 2 concentration/activator atomic concentration can be in a range of 0.4 to 2.5. In another embodiment, the scintillation crystal may have a decay time no greater than 40 ns, and in another embodiment, have the same or higher light output than another crystal having the same composition except without the Group 2 co-dopant. In a further embodiment, a boule can be grown to a diameter of at least 75 mm and have no spiral or very low spiral and no cracks. The scintillation crystal can be used in a radiation detection apparatus and be coupled to a photosensor.

A method of growing a rare-earth oxyorthosilicate crystal, and crystals grown using the method are disclosed. The method includes preparing a melt by melting a first substance including at least one first rare-earth element and providing an atmosphere that includes an inert gas and a gas including oxygen.

A phosphor composed by containing Ce.sup.3+ as a light emission center in a matrix garnet compound having a garnet structure. The matrix garnet compound is a solid solution composed of two or more end members, and the end members include Lu.sub.2CaMg.sub.2(SiO.sub.4).sub.3 as a first end member. It is preferable that the matrix garnet compound is a compound containing Al. A light emitting device uses the phosphor 2 and includes a solid-state light emitting device 117. The phosphor 2 is excited by light radiated by the solid-state light emitting device 117.

An infrared-excited infrared light emitting material and a preparation method thereof, and a security article for anti-counterfeit using thereof relate to a white to pale colored infrared-excited infrared light emitting material, a preparation method thereof, and an ink composition for anti-counterfeit containing the infrared exciting infrared light emitting material which visually appears white or colored, and is excited in the infrared region, emits light in the infrared region, but does not emit light in the visible region, and a security article requiring confirmation of authenticity and anti-counterfeit.