Luminescent Composites Research Articles

Effect of a Mo impurity on the luminescence properties of CdWO4, ZnWO4, and CaWO4

The thermoluminescence, the spectral composition of the x-ray luminescence and the thermoluminescence, the short-wave absorption, and the luminescence-excitation spectra were studied for ZnWO4, CdWO4, and CaWO4 single crystals with and without molybdenum impurities. The thermal-activation energies were found for radiationless transitions for all these crystals from the temperature dependence of the steady-state x-ray luminescence. A qualitative explanation for the results is offered.

Tritium detection by β-radioluminescence in standard media for thin-layer chromatography

The relative β-scintillation efficiencies of several thin-layer media of chromatography (“Merck” alumina and silica) have recently been determined at room and lower temperatures. In addition, we have now investigated the spectral composition of the emitted luminescence (for the most efficient media) to obtain a basis for choosing photomultiplier or film material with appropriate spectral response for optical detection. A broad-band emission (500–700 nm) was found, where a dominant peak at about 650 nm was due to gypsum admixture (as a binder). The sensitivity for tritium detection by luminescence was estimated.

Influence of temperature on the spectral composition of the zinc sulphide luminescence: I. Soudek, Brit. J. Appl. Phys., 11 (7), July 1960, 289–291

Influence of temperature on the spectral composition of the zinc sulphide luminescence: I. Soudek, Brit. J. Appl. Phys., 11 (7), July 1960, 289–291

Influence of temperature on the spectral composition of the zinc sulphide luminescence

The temperature dependence of the spectral composition has been presented by a new method which shows better the relative changes of the form of the emission band. On the main emission band of some zinc and zinc-cadmium sulphides, between the liquid air temperature and the temperature break-point, certain effects have been observed; these are that (a) below 180° K the short wave side of the emission band of all phosphors grows faster than the long wave side with increasing temperature, (b) that in the neighbourhood of 220° K, the intensity of the whole band has a minimum for all copper-activated and copper-contaminated phosphors, and that (c), above 220° K, some phosphors behave inversely as (a). These effects can be explained by the existence of two temperature-dependent processes having inverse influence on the form of the emission band, one being similar to the holemigration process and the other being in connexion with the thermal liberation of trapped electrons.

Spectral composition of the light of the Lantern-fish,Myctophum punctatum

Relative spectral emission curves are available for the lights of many invertebrate animals, but none exists for fish. It seems likely that many bony fish use their photophores to signal to one another. Information about the spectral composition of fish luminescence is desirable to permit comparisons with the spectral sensitivities of fish eyes, to enable calculations to be made of luminous intensities, and to allow estimates to be made of the rate of attenuation of such lights in sea water. To further these ends, measurements were made of the spectral composition of the luminescence of the lantern-fish,Myctophum punctatum.