A process for detecting oil or lubricant contamination in the production of an article by adding a Stokes-shifting taggant to an oil or lubricant of a machine utilized to produce the article or a component thereof, irradiating the articles produced with a first wavelength of radiation, and monitoring the articles for emission of radiation at a second wavelength. The taggant can be in the form of a composition containing a Stokes-shifting taggant, which absorbs radiation at a first wavelength and emits radiation at a second wavelength, different from said first wavelength, dissolved or dispersed in an oil or lubricant.

The present invention provides a gadolinium oxysulfide sintered body having a high light output. The problem is resolved by a gadolinium oxysulfide sintered body in which the ratio of the light transmittance T.sub.410 of 410 nm to the light transmittance T.sub.512 of 512 nm (T.sub.410/T.sub.512) is from 0.31 to 0.61, or a gadolinium oxysulfide sintered body in which the ratio of the diffraction peak intensity I.sub.y of a phase different from gadolinium oxysulfide appearing at 2θ=from 20 to 29° to the diffraction peak intensity (I.sub.x) of (102) or (011) of gadolinium oxysulfide appearing at 2θ=30°±1° (I.sub.y/I.sub.x) is 0.1 or less in an XRD diffraction pattern and which contains one or more activators selected from the group consisting of praseodymium, terbium, and cerium.

According to an embodiment, a radiation-scintillated shield which attenuates an incident radiation, includes a shielding part containing an activator-added gadolinium compound as an aggregate. The activator uses the gadolinium compound as a base material and emits light when struck by the radiation. Consequently, it becomes possible to shield a γ-ray and a neutron with a thickness which is about the same as that of a conventional concrete shield of γ-ray shield, and to confirm leakage of radiation.

The present disclosure is directed to a low cost sintering process for the preparation of gadolinium oxysulfide having a general formula of Gd.sub.2O.sub.2S, referred to as GOS, scintillation ceramics, comprising uniaxial hot pressing primary sintering and hot isostatic pressing secondary sintering.

Provided is a scintillator that includes: first phosphors each including an inorganic fluorescent compound; and a second phosphor including a fluorescent resin.

A value document system, a method for identifying a value document of a value document system, and a luminescent substance set, wherein the value document system includes at least a first value document and a second value document. The first value document has a security feature composed of a combination of at least a first and a second luminescent substance of a first or a second substance class. The second value document has a security feature with at least a first luminescent substance of the first or second substance class. The security feature of the first value document has at least a different intensity ratio of the emission, a different decay time ratio and/or a different decay time sum in two adjacent spectral ranges compared with the security feature of the second value document.

A problem addressed by the present invention is to provide a scintillator panel having excellent sensitivity and sharpness, and the spirit of the present invention is that the scintillator panel includes a base plate and a scintillator layer containing a binder resin and a phosphor, said scintillator layer further containing a compound represented by the following general formula (1) and/or a salt thereof;

##STR00001## (wherein, in the general formula (1), R represents a C.sub.1-30 hydrocarbon group; m represents an integer of 1 to 20; n represents 1 or 2; and when n is 2, a plurality of Rs may be the same or different).

A scintillator array includes: a structure having at least one scintillator segment and a first reflective layer, the at least one scintillator segment and the first reflective layer having a first surface and a second surface, the at least one scintillator segment having a sintered compact containing a rare earth oxysulfide phosphor, and the first reflective layer being configured to reflect light; and a second reflective layer provided above the first surface via an adhesive layer, the adhesive layer having a thickness of 2 μm or more and 40 μm or less, and the second reflective layer having a film configured to reflect light.

A fluorescent screen is configured to convert an X-ray into visible light to one embodiment. The screen includes a gadolinium oxysulfide phosphor activated with praseodymium and cerium. The phosphor contains praseodymium having a concentration of 0.01 mass % or more and 0.3 mass % or less and cerium having a concentration of 5 ppm or more and 30 ppm or less. An average particle diameter of the phosphor is 10 μm or more and 20 μm or less. A weight per unit area of the phosphor is 270 mg/cm.sup.2 or more and 380 mg/cm.sup.2 or less.

The present invention addresses the problem of providing a scintillator which has excellent impact resistance and favorable workability and moldability. The problem is solved by a resin-phosphor composite scintillator which contains a resin and a phosphor and is capable of converting irradiated radiation into visible light. In this composite scintillator, a brightness retention rate, which is measured 24 hours after 38-minute irradiation with an X-ray to a total irradiation dose of 13 kGy at a distance of 40 mm from a radiation source, is 65% or higher; the Rockwell hardness is 30 HRM or higher; and the content of the resin is not less than 10% by weight.