Mechanoluminescence and thermoluminesence in -irradiated rare earth doped crystals

✍ Scribed by Nameeta Brahme; D.P. Bisen; R.S. Kher; M.S.K. Khokhar

• Publisher: Elsevier
• Year: 2009
• Tongue: English
• Weight: 274 KB
• Volume: 2
• Category: Article
• ISSN: 1875-3892
• DOI: 10.1016/j.phpro.2009.07.028

✦ Synopsis

Mechanoluminescence (ML) and Thermoluminescence (TL -irradiated Dy, Ce, Er and Gd doped CaF 2 crystals were studied. The crystals of doped CaF 2 were grown by the Bridgman technique. The cleaved crystals were annealed at 450 0 C for about two hours and cooled very slowly and then irradiated for different time from 60 Co source having an exposure rate of 2.8x10 3 Gy/hr. ML was excited by applying uniaxial pressure on to the samples. Both the ML and TL intensities of CaF 2 crystals increase with doping of rare earth impurities. Both the ML and TL intensity of -irradiated Dy, Ce, Er and Gd doped CaF 2 crystals initially increase with increasing concentration of dopants obtaining an optimum value at irradiated Dy, Ce, Er and Gd doped CaF 2 crystals initially increases with the irradiation dose and then -doses. The order of ML and TL intensity for dopants were found similar and their order for decreasing intensity is CaF 2 : Dy> CaF 2 : Ce> CaF 2 : Er> CaF 2 :Gd. The ML spectra are almost similar to the TL spectra, this suggest that the centres emitting TL and ML may be the same although different processes cause their excitations.