Studying of manganese activated lithium tetraborate for its use in thermoluminescent dosimetry

Thermoluminescence (TL) of activated lithium tetraborate (Li2B4O7) produced in powder form show high sensitivity to ionizing radiation and may be of value for thermoluminescence dosimetry. In this thesis, the development of activated lithium tetraborate thermoluminescence dosimeter materials using solution combustion synthesis technique has been realized and their corresponding TL properties subject to various types of ionizing radiation were investigated. We specified the effect of synthesis and determined the TL response. Detection and mesurement of ionizing radiation have long been important in the physical and life sciences. Precise dosimetry has been particularly crucial in the application of radiation to medicine. During the last decades, for reasons that are well known, radiation dosimetry has become a matter of considerable concern to many other activities and groups: to civil and military branches and to many industrial enterprises. There has been an expanded interest and large research effort in the subject. The requirements of modern dosimetry for high local resolution of radiation fields, an extended detection range, independence of detector response from dose rate, etc., can often not fulfilled by conventional dosimetry technique, such as ionization chamber dosimetry. To a certain extent solid state techniques, particularly TL dosimetry (TLD) can cover these requirements. In this thesis, the behaviour of manganese as Li2B4O7 activator for its use as TL dosimetric material was examined. The thesis covered manganese activated lithium tetraborate preparation mainly the synthesis of lithium tetraborat using solution combustion synthesis (SCS), doping of activator into the doping material synthesized and changing of some parameters during the preparation procedure. After the synthesis stage the doping stage was followed where compound of Mn doped to lithium tetraborate using SCS method. In this project, thermoluminescence measurements of 5-10 mg activated lithium tetraborate was made with a "Riso TL/OSL reader (Model TL/OSL-DA-20)". Lithium tetraborate samples which were doped with different propotions were irradiated, during various times, with a beta source mounted in the reader. The TL glow curves and their variation with absorbed dose for lithium tetraborate activated with Mn was demonstrated. From the analysis of these graphs the best dose response, fading properties, reusability of this dosimetric material and the related dosimetric peaks were determined. Regarding to their being more obvious and stable for comparatively long periods of time in relation to exposure and measuring times the TL mechanisms of dosimetric peaks were selected and studied. Mn activator with the determined best preparation conditions showed to be a good activator for lithium borate. Characterization of the powder product was achieved by X-ray diffraction (XRD), Fourier transform Infra Red Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM) techniques. Increased understanding of the lithium tetraborate luminescence dosimetry, effective practices, findings and recommendations disseminated beyond the duration and scope of this thesis.