Measurements of Neutron Spectrum in the High-Energy DANE Accelerator Complex with an Extended Range Bonner Sphere Spectrometer

In the framework of the radiation protection monitoring around DANE, the high-energy factory of the Istituto Nazionale di Fisica Nucleare-Laboratori Nazionali di Frascati (INFN-LNF), a characterization of the neutron field was performed. As a suitable neutron spectrometer, a specially designed Bonner sphere system, whose energy range was extended up to hundreds mega-electron-volts by means of three spheres equipped with copper or lead inserts, was employed. The response matrix of the system was derived with MCNPX and experimentally validated with reference neutron fields. The neutron spectrum has been unfolded with the FRUIT (FRascati Unfolding Interactive Tool) code, a new unfolding code developed at INFN-LNF for the needs of operational radiation protection. This paper presents the results of the measurements in the DANE complex, underlying the achievements of the new unfolding code. Moreover, the impact of these kinds of measurements on routine radiation protection practices is briefly addressed.