Field calibration and comparison of personal neutron dosemeter designs based on CR-39 for the use around high-energy accelerators

Abstract PADC (poly-allyl-diglycol-carbonate) material, also known as CR-39, is widely used for the detection of charged particles. Additionally, thermal or fast neutrons can be measured through detection of secondary charged particles produced in a dedicated radiator material. Around high-energy accelerators neutron dose is mainly dominated by neutrons with energies above ∼ 1 MeV . In respect to radiation protection in such fields, the detection of fast neutrons is imperative and detection of thermal neutrons can be set aside. Providing that a dosemeter holder contains sufficient hydrogen as replacement of a dedicated radiator, the CR-39 detectors can easily be used in different dosemeter designs without losing sensitivity for high-energy neutrons. These considerations were taken into account when introducing the CR-39 detectors for individual neutron dosimetry at the high-energy accelerator facilities CERN and DESY. To demonstrate the feasibility of such an approach, measurements at the High-Energy Reference Field Facility (CERF) at CERN were performed with three different types of dosemeters using CR-39 detectors from two different manufacturers. The dosemeters were placed on all faces of Perspex phantoms at reference locations, in order to study the influence of the mounting position on the phantoms. Moreover, a field calibration factor was determined.