While, the age of Universe was estimated to be about 13.8 billion years. The age of Earth & Moon was estimated to be around 4.53 & 4.478 billion years respectively. From this, a comparative study was performed to find an efficient way for age calculation of the Universe. For Universe, 3 different methods were studied including Hubble constant, nucleocosmocronology & cooling of white dwarf stars. Rb-Sr dating was used for celestial objects like Earth & Moon. The detailed analysis was done with the help of Isochron graphs and with the knowledge of decay constant. Also, later radiocarbon dating of organic substance charcoal was performed and the age as a function of depth was determined. objects were studied involving Age of Universe, Earth & Moon. In this project, the radiometric dating for determination of age of celestial. By exploiting the knowledge of half-life and various decay schemes in radioactivity, determination of age has become possible. This technique of dating is dependent on radioactive materials and the concept of radioactivity. Radiometric Dating is one of the fundamental techniques through which estimation of age is done. Jüstel, Vorrichtung zur Messung des Reflexionsvermögens, DE10002294 View full-text It will also reveal the limits of this new technique. Our presentation sketches the technique and procedure for recording VUV reflection spectra and shows the results for several VUV phosphors. BaMgAl10O17:Eu2+ showing an almost independent and high light output in the respective wavelength range. This requires a specially prepared integration sphere, viz. To this end, all VUV photons reflected by the sample are converted to visible photons, which in turn are collected by an Ulbricht sphere and are finally counted by a PMT. The presented measurement technique allows the take up of reflectance spectra in the range from 120 to 300 nm (4 to 10 eV). While the recording of excitation spectra in the VUV range is an established method, reflection spectra are normally recorded not below 230 nm due to the absorption edge of the most common reflectance standards such as BaSO4 and CaCO3. Therefore, a complete optical characterization of VUV phosphors must involve measurements upon excitation in this wavelength range. Since the primary radiation spectrum of these devices is in the range between 140 and 200 nm, suitable phosphors must be efficient upon excitation in this regime, more precisely at 147 or 172 nm, which corresponds to the Xe atomic and Xe excimer. In recent years, VUV phosphors have attracted tremendous interest due to their application in plasma display panels and Xe excimer discharge lamps.
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