Radical kinetics and dosimetric features of gamma-irradiated disodium ethylenediaminetetraacetic acid

Dosimetric potential and kinetic features of disodium ethylenediaminetetraacetic acid (NaEDTA) were explored through a detail electron spin resonance (ESR) study performed at various temperatures on samples irradiated at various radiation doses. Irradiated NaEDTA was observed to exhibit an unresolved ESR spectrum consisting of many intense and weak resonance lines spread over a magnetic field range of about 7 mT and centered at g=2.00275. Findings derived from applied microwave power, long term storage investigation, and high and low temperature studies indicate that two radicals were formed after the irradiations. The spectroscopic parameters of these radicals were determined through spectrum simulation calculations. The dosimetric potential of NaEDTA was also investigated and it was concluded that NaEDTA does not present the characteristics of a good dosimetric material, but that ESR spectroscopy could be used in the discrimination of irradiated NaEDTA from the unirradiated one even long after irradiation. Activation energies of the involved species were also determined using the data derived from annealing studies performed at high temperatures.