Analysis of parameters that influence the amplitude of the ESR/alanine signal after irradiation.

When ESR/alanine dosimetry is used for comparison, the time elapsed between irradiation and measurement is critical. Several publications have already mentioned the need for monitoring some of the parameters before, during and after irradiation for accurate normalization of ESR measurements. Nevertheless, neither classification nor coupling effects have yet been mentioned. By application of an experimental design approach, some parameters such as temperature and humidity during storage, before and after irradiation, have been studied. Results are given about the way the signal tends to evolve, ranking the parameters according to their influence and the effects of parameter coupling. A comparison with a conventional approach (study of one parameter at a time) is made. It is proposed to use a normalized ESR measurement that better accounts for the chemical aspect. A better fit of the results (amplitude versus time) is observed when amplitude is corrected taking into account the water content of the dosimeter for a given relative humidity of the surrounding atmosphere during storage.