On the applicability of radionuclides emitting low energy X-rays for in situ radiotracer adsorption studies

In this paper, methodology and applicability of the in situ radiotracer 'thin gap' method are presented and discussed via some studies of Cr(VI) electroreduction on Pt electrode by measuring the low energy (E = 4.90 keV) X-rays of 51Cr used for labeling. Two types of scintillators, 2 mm thick β-plastic and 300 μm thick CaF2(Eu), were tested for nuclear detection. The plastic scintillator cannot be utilized for selective measurement of the soft X-rays emitted by 51Cr, hence, it does not allow us the estimation of the surface excess of chromium containing species on Pt electrode. In contrast to this, CaF2(Eu) is suitable for selective detection of low-energy X-rays; therefore, the radioelectrochemical cell equipped with the latter detector provides very promising measuring conditions for the extension of the radiotracer 'thin gap' method towards application of the low-energy X-ray emitters. (author)