Neutron spectrometry around a high-energy electron-positron collider using a multi-sphere system with passive detectors

At the INFN LNF (Frascati), the 510 MeV electron-positron collider DAPhiNE is operating since 1997. The neutron fields in the areas around the accelerator were characterised using a Bonner sphere system. The sensitivity of the system was extended up to 10(2) MeV by means of a lead loaded 12(') sphere. Recently developed thermoluminescence dosemeters (TLDs), with improved neutron sensitivity and gamma rejection properties, were used as central detectors. The new TLD-based spectrometric system was characterised by irradiation in quasi-monoenergetic or radionuclide neutron fields. In addition, numerical verifications with the Monte Carlo code MCNP were performed. This work addresses this new TLD-based spectrometer and presents the spectral measurements performed in a point of test around DAPhiNE. The results are compared with those obtained, in the same point, with a previously validated Bonner sphere system based on an active (6)LiI(Eu) scintillator.