Dosimetria neutrònica i gamma en un ciclotró de 18 MeV durant la producció de radionúclids emissors de positrons (projecte coordinat)

The main objective of this project is to carry out a dosimetric study, of neutron and gamma radiation, inside and outside a cyclotron bunker of Cyclone 18/9 type (with proton and deuteron energies of 18 MeV and 9 MeV, respectively) during production of positron emitting radionuclides in order to determine the source term of this cyclotron. On the other hand, we attempt to study the appropriateness of diverse radiation measurement systems. Thus, for neutron spectrum measurements we will employ a spectrometric system of Bonner spheres based on a He-3 proportional counter. The global magnitudes will be measured using bubble dosimeters and pulse counters. For gamma measurements, TLD personal dosimeters together with a Geiger probe and an ionisation chamber will be used. Monte Carlo simulation will be performed to model the neutron energy spectrum and the dose equivalent, inside and outside the cyclotron bunker, from the source term that would be validated with the spectrometric measurements. In addition, a mathematical human shaped phantom will be simulated by Monte Carlo techniques in the different measurement points to evaluate the correctness of the neutron dose readings as estimator values of the effective doses that could receive a man pattern. The radiation levels inside and outside the cyclotron bunker could be contrasted with the respective security studies of this installation. This would be useful to design new similar installations and will permit the effective dose estimation in any eventual accident