A novel experimental approach to characterize neutron fields at high- and low-energy particle accelerators

Abstract

The characterization of particle accelerator induced neutron fields is challenging but fundamental for research and industrial activities, including radiation protection, neutron metrology, developments of neutron detectors for nuclear and high-energy physics, decommissioning of nuclear facilities, and studies of neutron damage on materials and electronic components. This work reports on the study of a novel approach to the experimental characterization of neutron spectra at two complex accelerator environments, namely the CERF, a high-energy mixed reference field at CERN in Geneva, and the Bern medical cyclotron laboratory, a facility used for multi-disciplinary research activities, and for commercial radioisotope production for nuclear medicine. Measurements were performed through an innovative active neutron spectrometer called DIAMON, a device developed to provide in real time neutron energy spectra without the need of guess distributions. The intercomparison of DIAMON measurements with reference data, Monte Carlo simulations, and with the well-established neutron monitor Berthold LB 6411, has been found to be highly satisfactory in all conditions. It was demonstrated that DIAMON is an almost unique device able to characterize neutron fields induced by hadrons at 120 GeV/c as well as by protons at 18 MeV colliding with different materials. The accurate measurement of neutron spectra at medical cyclotrons during routine radionuclide production for nuclear medicine applications is of paramount importance for the facility decommissioning. The findings of this work are the basis for establishing a methodology for producing controlled proton-induced neutron beams with medical cyclotrons.

Ultra-high dose rate dosimetry with miniaturized scintillation detectors coupled to optical fibers

“…The Bern cyclotron laboratory is equipped with an IBA Cyclone HC, accelerating Hions to a kinetic energy of 18 MeV with a maximum current of 150 µA 13 . In addition to the commercial radioisotope production for Positron Emission Tomography (PET), the Bern cyclotron is used for multi-disciplinary research activities, including studies of novel radioisotopes for nuclear medicine 14,15 , developments on particle accelerators and detectors 16 , studies of environmental physics 17 and radiation hardness 18,19 . These activities are possible thanks to a 6-meter long Beam Transfer Line (BTL) ending in a separate bunker with independent access to the experimental area.…”

Novel solid target and irradiation methods for theranostic radioisotope production at the Bern medical cyclotron

“…5-a) for further analysis or for transport to external research laboratories. To assess the produced activity, the receiving station was equipped with a CZT detector system based on a ∼1 cm 3 CdZnTe crystal (GBS Elektronik), shown in Fig. 5-b.…”

“…The facility hosts an IBA Cyclone 18/18 HC medical cyclotron (18 MeV proton beams, maximum current of 150 𝜇𝜇A), equipped with 6 liquid targets for *Corresponding author: gaia.dellepiane@lhep.unibe.ch routine 18 F production, an IBA Nirta Solid Target Station (STS) and a 6 m long Beam Transport Line (BTL) that brings the beam in a second bunker with independent access to the experimental area. This solution allows multidisciplinary research activities [2][3][4] to be carried out in parallel with the industrial production of 18 F-labelled PET radiotracers.…”