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Irradiation of starch is of much importance to get rid of microbes and for disinfection. EPR study of the ionizing radiation-induced radicals can lead to the assessment of radiation doses delivered during irradiation. The EPR spectra properties, microwave power saturation behavior, short- and long-term temporal dependencies, and other significant factors are studied. Response of EPR spectra of irradiated starch over the range (0.5–10 kGy) was investigated. The time dependence study of the radiation-induced signal radicals of starch showed that variation of the EPR signal can be noticed within ±7.7% relative to the average value over 38 days following irradiation. Results obtained indicate that gamma irradiated starch can be identified and radiation doses can be determined accurately using EPR spectroscopic techniques. [ABSTRACT FROM AUTHOR]

Taurine/EPR rods (3 × 10 mm) have been prepared by a simple technique in the laboratory where taurine powder was mixed with a molten mixture of paraffin wax and an ethylene vinyl acetate (EVA) copolymer. The binding mixture EVA/Paraffin does not present interference or noise in the EPR signal before or after irradiation. The rods show good mechanical properties for safe and multi-use handling. An EPR investigation of radiation induced radicals in taurine rods revealed that there are two types of radicals produced after exposure to gamma radiation (60Co). EPR spectra were recorded and analyzed - also the microwave power saturation and modulation amplitude were studied and optimized. Response of taurine to different radiation doses (1.5-100 kGy) was studied and found to follow a linear relationship up to 100 kGy. Radiation induced radicals in taurine persists and showed a noticeable stability over 94 days following irradiation. Uncertainities associated with the evaluation of radiation doses using taurine dosimeters were discussed and tabulated. It was found that taurine possesses good dosimetric properties using EPR spectroscopy in high doses in addition to its simple spectrum.

In the current study, the EPR signal of both gamma-irradiated shell and kernel of the pistachio is recorded and investigated. The spectrum properties, microwave power dependency of signal intensities, short- and long-term temporal dependencies, and other significant factors are studied. This investigation was done on how varying radiation doses (0–10 kGy) affected the reactions of pistachio shells and kernels. The time dependence of the radiation-induced signal intensity of pistachio showed that the maximum intensity reached about 98.75% and 67% of its original value for shells and kernels, respectively, after the first six hours. These results indicate that EPR is an effective tool for gamma-irradiated pistachio identification and dosimetry, whether employing pistachio shells or kernels. [ABSTRACT FROM AUTHOR]

The main thrust of this work is the investigation of performance of relatively new commercial LaBr3:Ce probe (Inspector 1000™ with LaBr3:Ce crystal) for gamma-ray spectroscopy and dosimetry measurements in comparison to LaCl3:Ce and NaI:Tl scintillators. The crystals were irradiated by a wide range of energies (57Co, 22Na, 18F, 137Cs and 60Co). The study involved recording of detected spectra and measurement of energy resolution, photopeak efficiency, internal radioactivity measurements as well as dose rate. The Monte Carlo package, Geant4 Application for Tomographic Emission (GATE) was used to validate the experiments. Overall results showed very good agreement between the measurements and the simulations. The LaBr3:Ce crystal has excellent energy resolution, energy resolutions of (3.37±0.05)% and (2.98±0.07)% for a 137Cs 662keV and a 60Co 1332keV gamma-ray point sources respectively, were recorded. The disadvantage of the lanthanum halide scintillators is their internal radioactivity. Inspector 1000™ with LaBr3:Ce scintillator has shown an accurate and quick dose measurements at Positron Emission Tomography (PET) Units which allows accurate assessment of the radiation dose received by staff members compared to the use of electronic personal dosimeters (EPD). [ABSTRACT FROM AUTHOR]