Status of current developments and applications of two accelerators in Mexico

At the 'Instituto Nacional de Investigaciones Nucleares' of Mexico there are three accelerators. A home made Pelletron type electron accelerator, with a beam energy from 0.15 to 1.1 MeV, a Tandem Van de Graaff accelerator with a variable voltage from 1 to 6 MV, and a multipurpose Tandetron accelerator with a maximum voltage of 2 MV, both Tandem and Tandetron accelerators have SNICS ion sources. Some studies performed with the Pelletron type accelerator are: Radiation effects on waste water samples with different pH showed that an absorbed dose of 12 kGy, reduced more than 99.5% Benzene concentration, more than 98% toluene and more than 97% phenol. Similar contaminants, concentrations, irradiation conditions and results have been obtained for treatment of sewage sludge samples. An electron beam was used for simulating gamma irradiation for qualification of paint coatings. The radiation test on paint coatings was performed as a request from our nuclear power facility with doses defined by the Safety Analysis Report of a BWR Type Mark II. A comparison of two sets of paint-coating specimens irradiated, one set with a gamma beam, and second one with an electron beam, was made. A commercial Co 60 gamma source at a dose rate of 4.55 kGy/h, 8 kGy/h and 10 kGy/h and doses up to 725 kGy was used for gamma irradiation whereas an electron beam of 0.8 MeV produced dose rates from 5 MGy/h to 10 MGy/h according with the electron beam intensity. Dose was determined by bulk etching velocity of LR115 track detectors. For this purpose alpha irradiated and blank detectors were exposed to an increase of electron doses from 10.5 to 317.5 kGy. After irradiation the detectors were etched under routine conditions. The variation of the bulk etching velocity as a function of each one of the electron doses supplied was interpolated in order to obtain dosimetric response curves. (author)