The study of dosimetric properties of sulfanilic acid in low radiation dose range using the ESR technique

Abstract

The development of new dosimeters with good dosimetric properties is important for quality control in radiation applications. In this study, the potential of sulfanilic acid (C6H7NO3S) powder form, as a dosimeter in low-dose ionizing radiation (<30 Gy), was analyzed by an Electron Spin Resonance spectrometer (Bruker EMX-131 X-band). Gamma irradiations were performed at room temperature (290 K) using a 60Co gamma cell supplying a dose rate of 32 Gy/h and X photon irradiations at 6 and 18 MV energies were performed using a variant DHX model clinical linear accelerator (Linac) at a dose rate of 3 Gy/min. While unirradiated (control) sulfanilic acid exhibited no ESR signal, the irradiated sample showed a single-line ESR spectrum spread over a magnetic field range of 100 G, as shown in Figure 2. Variations of the peak heights with the sample mass irradiated at 2 Gy gamma dose were studied in the range of 130–330 mg. The ESR signal intensity observed at g-factor = 2.0053 of this compound is dependent on sample mass, so ∼250 mg was chosen at each step of the study. The paramagnetic center formed in the gamma-irradiated sulfanilic acid was followed over 50 days. The dose-response curves were given in the dose range from 0.05 to 10 Gy for the sample exposed to gamma radiation and for the sample exposed in the range of 0.05 Gy–30 Gy at 6 and 18 MV X-ray energies. The fitting values of the function that best describes dose-response curves are calculated. In the g value region, where the ESR signal was observed in the irradiated sample, the lowest dose value at which the signal could be read was 50 mGy, significantly different from the noise. With all these investigations, sulfanilic acid can be used to estimate gamma radiation dose within boundary conditions in medical applications.