Abstract: A scintillator is disclosed that comprises a ceramic of a rare-earth oxysulfide activated with Pr, such as Gd.sub.2 O.sub.2 S:Pr, having: (1) a ratio of a peak value at about 270 K to that at about 140 K in a glow curve of about 0.01 or less, when the thermoluminescence intensity of the scintillator is measured at a rate of temperature increase of 15.+-.5 K/min after 20 minutes irradiation with ultraviolet rays having a wavelength of 254 nm and a power of 1 W/m.sup.2 at liquid nitrogen temperature, and (2) a ratio of a peak value at about 630 nm to that at about 512 nm of a thermoluminescence of about 410 K with about 2 nm resolution of about 1 or less.

Abstract: A fluorescent substance is comprised of a rare earth oxysulfide represented by the chemical formula, R.sub.2(1-x) Pr.sub.2x O.sub.2 S, wherein R stands for at least one member selected from the group consisting of Y, Gd, La, and Lu and x for a numerical value satisfying the expression, 5.times.10.sup.-5 .ltoreq.x.ltoreq.1.times.10.sup.-2, and has a linear absorption coefficient of not more than 6.0 cm.sup.-1 at 550 nm. And further fluorescent substance contains PO.sub.4 in an amount of not more than 100 ppm.

Abstract: A single crystal of a compound comprises a single crystal of a compound at least part of components is of the above mentioned material decomposed at a temperature around the melting point, having a volume of 5 cc or more, and deviation of respective elements in a composition of the single crystal from the stoichiometric composition is within the range of .+-.5%.

Abstract: A single crystal of a compound comprises which easily decomposes at a temperature around the melting point and evaporates at least a part of the compound having a volume of 5 cc or more and a composition deviation of respective elements from the stoichiometric composition of the compound being within the range of .+-.5% in terms of weight ratio.

Abstract: An X-ray detector has a transmission type intensifying screen provided on the X-ray incident area of the detector body and a reflection type intensifying screen provided on the inner wall surface of the detector body except for the X-ray incident area. Visible rays from the transmission type intensifying screen and the reflection type intensifying screen are detected by a photomultiplier installed in the detector body. The transmission type intensifying screen and the reflection type intensifying screen use fluorescent materials such as Gd.sub.2 O.sub.2 S:Tb; Gd.sub.2 O.sub.2 S:Tb, Ce; GD.sub.2 O.sub.2 S:Tb, Yb; Gb.sub.2 O.sub.2 S:Pr; BaFCl:Eu; BaFBr:Eu; La.sub.2 O.sub.2 S:Tb; La.sub.2 O.sub.2 S:Tb, Ce; La.sub.2 O.sub.2 S:Tb, Yb; La.sub.2 O.sub.2 S:Pr; Y.sub.2 O.sub.2 S:Tb; Y.sub.2 O.sub.2 S:Tb, Ce; Y.sub.2 O.sub.2 S:Tb, Yb; and Y.sub.2 O.sub.2 S:Pr.

Abstract: Rare earth oxysulfide ceramic material prepared by covering the material with a foil of a metal selected from the group consisting of molybdenum, tungsten, platinum, and rhenium, sealing it into an airtight vessel of tantalum or niobium, and then subjecting it to a hot isostatic press process.

Abstract: This invention concerns an intensifying screen using a phosphor capable of emitting light under X-ray excitation. This intensifying screen is characterized by the fact that the phosphor layer in the intensifying screen comprises a first phosphor layer containing a phosphor represented by the general formula (I):M.sub.a Ln.sub.1--x--(2/3)a DO.sub.4 :XR.sup.3+ (I)(wherein M stands for at least one divalent metal element selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and Cd, Ln for at least one element selected from the group consisting of Y, Gd, La, and Lu, D for either or both of Ta and Nb, R for at least one member selected from the group consisting of Tm, Pr, Sm, Eu, Tb, Dy, Yb, and self-activators, a for a value satisfying the expression, 0<a.ltoreq.1, and x for a valve satisfying the expression, 0.ltoreq.x.ltoreq.0.005) and formed on the aforementioned substrate side and a second phosphor layer containing CaWO.sub.4 and formed on the aforementioned protective layer side.

Abstract: There is provided a method of manufacturing a ceramic, wherein a ceramic material is covered with a foil of a metal selected from the group consisting of molybdenum, tungsten, platinum, and rhenium, sealed into an airtight vessel of tantalum or niobium, and then subjected to a hot isostatic press process. The method of the present invention can suppress coloration produced in the hot isostatic press.

Abstract: A radiographic intensifying screen having improved modulation transfer function and/or sensitivity. The radiographic intensifying screen of the present invention comprises a support, a phosphor layer formed on the support, a protective film formed on the phosphor layer, wherein the phosphor layer includes a small phosphor particles layer at its support side consisting essentially of small phosphor particles with an average grain size of about 4 .mu.m or less and a binding agent; and a mixed large and small phosphor particles layer at its protective film side consisting essentially of large phosphor particles with an average grain size ranging from about 7 to 20 .mu.m, small phosphor particles present in the interstices of the large phosphor particles and with an average grain size of about 4 .mu.m or less and a binding agent.

Abstract: An X-ray conversion screen having reduced afterglow without any appreciable loss in the brightness under X-ray excitation comprises a substrate and at least one fluorescent layer applied thereto, the fluorescent layer containing a fluorescent substance which comprises terbium-activated lanthanum or gadolinium oxyhalide having yttrium or lutetium and, as desired, ytterbium added thereto as impurities.