0000000000671266
AUTHOR
L. Trinkler
Stimulated luminescence of AlN ceramics induced by ultraviolet radiation
Abstract Properties of thermally stimulated luminescence (TL) and optically stimulated luminescence (OSL) of the ceramic material AlN-Y 2 O 3 have been studied after exposure to ultraviolet radiation (UVR). The dosemeter material Al 2 O 3 : C has been used for comparative measurements. The spectral sensitivity of the samples has been studied and compared with spectral effectiveness of the UVR-induced biological processes. It has been shown that a very high yield and linear dose response characterise the UVR-induced TL from AlN-Y 2 O 3 . Although lower than the TL, the OSL signal from UV-exposed AlN-Y 2 O 3 is still higher than that of Al 2 O 3 : C in a broad spectral region. The possibilit…
Thermoluminescence properties of AlN ceramics
Abstract The paper describes thermoluminescence (TL) properties of AlN:Y 2 O 3 ceramics irradiated with ionising radiation. A high TL sensitivity of AlN:Y 2 O 3 ceramics to radiation encouraged a study of the AlN ceramics for application as a dosimetric material. The paper presents experimental data on: glow curve, emission spectrum, dose response, energy dependence, influence of heating rate and fading rate. The measured TL characteristics were compared with those of well-known, widely used TLDs, i.e. LiF:Mg,Ti, LiF:Mg,Cu,P and Al 2 O 3 :C. It is concluded that AlN:Y 2 O 3 ceramics showing a radiation sensitivity which is approximately 50 times greater than that of LiF:Mg,Ti is an interest…
Photoluminescence excitation spectroscopy in boron nitride nanotubes compared to microcrystalline h‐BN and c‐BN
Photoluminescence spectra and photoluminescence excitation spectra have been measured on samples of hexagonal boron nitride microcrystalline powder, cubic boron nitride single crystal, and boron nitride nanotubes (mixture of single-walled and multi-walled with some h-BN precursor). The reason for studying these 3 samples in a comparative fashion is that nanotube BN, while based on a rolled hexagonal-BN (sp2-bonded) sheet, is expected to take on more sp3 bond-character reminiscent of cubic-BN as the curvature becomes tighter. With some simplicity of statement, this study was planned to view spectroscopy of nanotube BN with respect to its two limiting cases of bond character, all measured in …
Luminescence of impyrity and radiation defects in magnesium oxide irradiated by fast neutrons
Abstract The photoluminescence, its excitation and absorption spectra of MgO single crystals are investigated before and after the irradiation with fast neutrons. It is shown that the fast neutron irradiation leads to the formation of two types of centers: the interstitial proton H + i and the Mg(OH) 2 microphase. From the behaviour of the photoluminescence (PL) and its excitation (PLE) spectra we suppose that the photoluminescence band at 730 nm of the MgO crystals belongs to the complex V − OH − Fe 3+ centers, which is transformed during the irradiation with fast neutrons. The obtained results allow assume that the transitionions play an important role in the migration of vacancies and in…
Optical properties of natural topaz
The results of investigation of infrared, Raman and UV-Visible absorption spectra of natural topaz crystals from Ukraine before and after fast neutron irradiation are presented. We assume that the ~ 620 nm band in topaz crystals is associated with the presence of Cr 3+ , Fe 2+ and Mn 2+ impurities. The broad band with maxima at 650 cm -1 observed in Raman spectra for topaz irradiated by fast neutrons may be connected with lattice disorder. Exchange interaction between radiation defect and impurity ions during neutron irradiation leads to appearance of additional absorption band in UV-VIS spectra and bands broadening in infrared and Raman spectra of investigated crystals.
Aluminium nitrate ceramics: a potential UV dosemeter material.
The ceramic material AlN-Y 2 O 3 is proposed as a potential ultraviolet radiation (UVR) dosemeter using optically stimulated luminescence (OSL) and thermally stimulated luminescence (TL). Experimental studies have shown that AlN ceramics exhibit attractive characteristics suitable for practical UV dosimetry applications. The features are: (1) the spectral sensitivity covers the 200-350 nm range, in the UV-B region it is similar to that of human skin; (2) the angular dependence of the incident radiation follows the cosine law; (3) high yields of both UVR-induced OSL and TL signals compared to those of Al 2 O 3 :C; and (4) a large dynamic range TL signal (5 orders of magnitude). Although ther…