New approaches to retrospective dosimetry using cementitious building materials

OPTICALLY STIMULATED LUMINESCENCE PROPERTIES OF COMMERCIALLY AVAILABLE KCL DIETARY SUPPLEMENTS AS RETROSPECTIVE DOSIMETERS

In the case of an unexpected exposure to radiation in places where there is no access to standard dosimeters, materials that can act as detectors in methods of retrospective dosimetry are looked for. Such materials include, but are not limited to, medicines and dietary supplements that are found in households or in personal bags. This paper presents the optically stimulated luminescence (OSL) dosimetric properties of dietary supplements, the main ingredient of which is a sensitive phosphor - potassium chloride (KCl). Three types of potassium chloride dietary supplements were tested and and compared to a selection of four common drugs in terms of their sensitivity. Basic dosimetric properties of dietary supplements such as signal repeatability, dose response and fading were determined. The dose recovery test was performed two and seven days after exposure to radiation. The obtained dose values for the two supplements showed good compliance with the nominal dose values and the possibility of correctly assigning the doses to the levels of triage (low dose 0-1 Gy, medium dose 1-2 Gy and high dose > 2 Gy). The presented results show that dietary supplements with KCl have the potential to be used as emergency detectors in the dose recovery process.

DEVELOPMENT OF NACL-BASED OPTICALLY STIMULATED LUMINESCENT PHOSPHORS FOR THE POSSIBLE APPLICATIONS IN DOSIMETRY

New highly sensitive optically stimulated luminescent phosphors with NaCl moiety and dopants Ca,Cu,P/Mg,Cu,P are developed. These phosphors show very high optically stimulated luminescence (OSL) sensitivity. The dose response for NaCl:Ca,Cu,P is linear up to 1.2 Gy and for NaCl:Mg,Cu,P is slightly sub linear from 0.2 Gy. These phosphors show 30% fading during first 4 and later signal gets stabilised with no further signal loss. These sensitive phosphors will find applications in radiation dosimetry using OSL.

Thermoluminescence properties of annealed natural quartz after beta irradiation

Here we investigated the effects of annealing, heating rate and fading (after annealing at 800 °C) on the thermoluminescence (TL) glow curves of natural quartz (NQ). All of the samples were annealed at different temperatures between 100 °C and 800 °C and then irradiated with a beta dose of about 34 Gray (Gy), in order to determine the effects of annealing treatments on TL peaks of natural quartz. TL glow curves of the samples were recorded. It was observed that the intensities of TL peaks were strongly sensitive to annealing temperatures at 800 °C. The heating rate and fading effect of TL peaks of natural quartz were examined for the annealed samples at 800 °C for 30 min. It was observed that the intensities of the TL peaks were differently affected from heating rate and fading. Additionally, TL kinetic parameters (activation energy, frequency factor and order of kinetics) of all peaks were determined for annealed samples using a computerized glow curve deconvolution (CGCD) method and Mathematica software. Copyright © 2016 John Wiley & Sons, Ltd.

Luminescence dosimetry using building materials and personal objects

There is a growing public awareness of the risk of accidental radiation exposure due to ageing nuclear power installations, illegal dumping of nuclear waste and terrorist activities, and of the consequential health risks to populations in addition to social and economic disturbance extending beyond national boundaries. In the event of catastrophic incidents where no direct radiation monitoring data are available, the application of retrospective dosimetry techniques such as luminescence may be employed with materials from the immediate environment to confirm values of cumulative gamma dose to compare with or augment computational modeling calculations. Application of the method to post-Chernobyl studies has resulted in the development of new procedures using fired building materials with the capability to measure cumulative doses owing to artificial sources of gamma radiation as low as 20 mGy. Combined with Monte Carlo simulations of photon transport, values of cumulative dose in brick can be presented in a form suitable for use in dose-reconstruction efforts. Recent investigations have also shown that certain types of cementitious building material, including concrete, mortar and plaster, and personal objects in the form of telephone cards containing microchips and dental ceramics have the potential to be used for retrospective dosimetry. Examples of the most recent research concerning new materials and examples of application to sites in the Former Soviet Union are discussed.