Nano-structured, radiation sensitive materials for nuclear-medical and border protection applications (2016 - 2017)
Project coordinator - Dr. Juris Prikulis, ICP UL
Scientific and/or technological objectives
The overall aim of the project the development of new nano-materials for integration dosimetry with use in personal-dosimeter monitoring. These serve in nuclear industry, nuclear medicine, border protection, etc. areas.
Overall project budget - 334,915 EUR
The proposed consortium of 4 organizations, University of Latvia (UL-Latvia), Institute of Electrophysics (UB RAS-Russia), Cologne University of Applied Sciences (CUAS-Germany) and National Institute of Physics and Nuclear Engineering (IFINE-Romania), aims to pool resources for achieving a common goal - development and comparative study of new nano - structured radiation sensitive materials for application in nuclear – medical and border protection applications.
The use of radiation technologies requires accurate and reliable dosimetry due to cumulative nature or radiation effects on the human health. A type of passive dosimeters, the thermoluminescent dosimeters (TLD), is widely used and their operation principle is based on response of a phosphorus material to ionizing radiation. It has been observed that TL dosimetric response of nano-phosphorus has an increased dose range with good linearity over its microcrystalline counterparts. It also accommodates a considerably higher measured dose upper limit. This characteristic is of marked interest in such areas as radiation therapy of cancer, where extremely high doses are delivered to the tumour volume, and border protection where exposure to unknown source is potentially possible.
The novelty of the project is in developing surface enhanced nano-structured materials, nano-powders and coatings of simple and complex metal oxides by pulsed electron evaporation and magnetron sputtering methods – with the aim of higher glow and better transparency. The materials will be irradiated for tests with relevant radionuclide sources and following dose response efficiency measurements, dose linearity region and fractional glow curve analysis will be performed. The detailed Glow Curve Analysis for each type of radiation will be developed to improve the accuracy of dose readings, characterize the statistical fluctuations of materials used and comparatively assess the advantages of each material under the test.
WP4 and team leader Dr. Krišjānis Šmits, ISSP UL, other members Dr.habil.phys.Larisa Grigorjeva, Dr.habil.phys. Donats Millers
WP 4 - TLD and OSL analysis of irradiated nano-structured materials
The thermo-stimulated luminescence of the irradiated materials will be then measured and recorded at UL ISSP. The light sum under the glow curve gives the most accurate dose reading, however we will determine if the phosphors require pre-/post irradiation annealing for (shallow level) trap-stabilisation and better reproducibility. The shape of the glow curve, determined by the heating rate, will allow us to determine the mono-energetic traps, or trap distribution accordingly. For the latter we will develop fractional glow curves with different heating rates. The dose linearity region will be established for each material and the responses compared. We are interested also in a non-linear calibration curve for higher accuracy – as this region is mildly non-linear.