Evaluation of some parameters which influence the ESR measurements for the fading study of alanine dosimeters

Abstract

Since several years, with the evolution of ESR spectrometers, the measurement of low absorbed doses seems to be accessible by alanine dosimetry. Some laboratories have realized important progress in this domain, but the influence of external physical and chemical factors that modify the results (fading) is not well quantified for using them with a sufficient accuracy for national or international comparisons, typically less than 3%. The first experimental study of combined effects has been realized in our laboratory. A necessary multiparametric approach (experimental design) has shown the complexity of the problem to solve before creating a physico-chemical model of the observed phenomena. The chosen methodology permits us to give the first quantitative approach of the fading for applied metrology.

Dosimetry of ionising radiation

“…In dosimetry, the amplitude of the central peak on the spectrum is measured. The relation between this amplitude and the dose received by the sample depends on numerous factors that can be classified in two categories [Dolo et al, 1998;:…”

Electron paramagnetic resonance of radicals induced in drugs and excipients by radiation or mechanical treatments

“…3) seems also simple: the unirradiated samples show no ESR signal, and the irradiated ones show large signals, more or less complex, depending on the chemical nature of the amino-acid. Generally, the storage time is very important (several months, even years) and even used, in case of alanine, for dosimetry [19,20]; for some of them a storage time of 2 years does not show any important evolution in the shape of the EPR signal (alanine, arginine, glycine); to see such an evolution, it is necessary to heat the sample during several hours at 70°C (for example, glycine). The great majority of amino-acids (histidine, lysine, proline, tyrosine, fects observed by other techniques such as microelectrophoresis or electronic microscopy [21].…”

The use of ESR spectroscopy for the investigation of dosimetric properties of egg shells

“…uven, 2000). The advantage that ESR measurements have is that they can be done without heating the material, which allows us to use tissue equivalent organic crystalline amino acids (alanine) as a dosimeter element (Regulla and Deffner, 1982;Bergstrand et al, 1998;Dolo et al, 1998;Ikeya, 1993) and biological materials to determine nuclear accident dose (Ishii et al, 1990;Desrosiers, 1991a;Ikeya, 1993). The ESR technique has also been applied to the identification of irradiated foods (Dodd et al, 1985;Desrosiers and Simic, 1988;Raffi et al, 1989;Desrosiers, 1989;Desrosiers, 1991b;Desrosiers et al, 1993) and to the dating of human and animal remains (Ikeya and Miki, 1980;Kai et al, 1988;Ikeya ,1993).…”