The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A.sub.2HfO.sub.3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

The present invention related to a nitride phosphor represented by the following general formula (1), the nitride phosphor having an x value of less than 0.43 in luminescent color coordinates (x, y) upon being excited with excitation light of 455 nm, and a reflectance Ra of 89% or more at 770 nm;
Ln.sub.xSi.sub.yN.sub.n:Z(1),
wherein Ln is a rare-earth element excluding the element used as an activator, Z is an activator, x satisfies 2.7x3.3, y satisfies 5.4y6.6, and n satisfies 10n12.

A production method of a phosphor includes firing a starting material mixture in a nitrogen atmosphere at a temperature range between 1,500 C. inclusive and 2,200 C. inclusive. The starting material mixture is a mixture of metallic compounds, and is capable of constituting a composition including M, A, Al, O, and N (M is Eu; and A is one kind or two or more kinds of element(s) selected from C, Si, Ge, Sn, B, Ga, In, Mg, Ca, Sr, Ba, Sc, Y, La, Gd, Lu, Ti, Zr, Hf, Ta, and W) by firing.

The present invention relates generally in part to BeO-based compounds that are capable of storing at least part of the energy of incident ionizing radiation and releasing at least part of the stored energy upon optical stimulation and heating. BeO-based compounds dosimetry was also developed in instrumentation, application and fundamental investigations. The present disclosure further relates the to the investigation of a BeO-based optically stimulated luminescence (OSL) dosimeter together with an OSL reader, and discusses the design and operation of an OSL reader, suitable to measure OSL emission of BeO-based dosimeters, for example beryllium oxide doped with sodium, dysprosium and erbium. The present disclosure further relates to the use of BeO-based compounds comprising BeO and at least one dopant selected from the group consisting of sodium, dysprosium and erbium as a fiber-coupled OSL dosimeter.

The invention provides, amongst others for application in a lighting unit, a phosphor having the formula M.sub.1xyzZ.sub.zA.sub.aB.sub.bC.sub.cD.sub.dE.sub.eN.sub.4nO.sub.n:ES.sub.xRE.sub.y (I), with M=selected from the group consisting of Ca, Sr, and Ba; Z=selected from the group consisting of monovalent Na, K, and Rb; A=selected from the group consisting of divalent Mg, Mn, Zn, and Cd; B=selected from the group consisting of trivalent B, Al and Ga; C=selected from the group consisting of tetravalent Si, Ge, Ti, and Hf; D=selected from the group consisting of monovalent Li, and Cu; E=selected for the group consisting of P, V, Nb, and Ta; ES=selected from the group consisting of divalent Eu, Sm and Yb; RE=selected from the group consisting of trivalent Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm; 0x0.2; 0y0.2; 0<x+y0.4; 0z<1; 0n0.5; 0a4 (such as 2a3); 0b4; 0c4; 0d4; 0e4; a+b+c+d+e=4; and 2a+3b+4c+d+5e=10yn+z.

The present invention enables us to achieve both further fine particle size reduction and uniformity of particle size distribution of metal oxide nanoparticles.

The present invention is a method for producing metal oxide nanoparticles that consists of a process for obtaining metal oxide nanoparticles by mixing a supercritical, subcritical, or gas phase aqueous material and an organometallic complex solution, wherein the mixing time is controllable within the range of 0.015 s to 380 s and the diameter of at least one of the average primary particle diameter or the crystallite diameter of the nanoparticles can be controlled within the range of 1.0 nm to 9.0 nm, and the coefficient of variation of the diameter can be controlled within 0.5 nm or less by controlling the mixing time. The resulting nanoparticles encompass metal elements capable of forming organometallic complexes. Additionally, the organic molecules are strongly bonded to the most unstable surface.

A wavelength conversion device includes a phosphor member and a plurality of nanoantennas. The phosphor member has one surface on which an excitation light is incident, includes a phosphor excited by the excitation light to emit a fluorescence, and has an uneven structure on another surface in an opposite side of the one surface. The uneven structure includes a plurality of projecting portions each provided in one direction along the other surface at a pitch smaller than a peak wavelength of the fluorescence. The plurality of nanoantennas are provided at upper surfaces of the plurality of projecting portions and made of a metal material.