Performance Tests of Survey Instruments used in Radiation Fields Around High-Energy Accelerators

Measurements of ambient dose equivalent in stray radiation fields behind the shielding of high-energy accelerators are a challenging task. Several radiation components (photons, neutrons, charged particles), spanning a wide range of energies, contribute to the total dose equivalent. Usually for measurements of the total dose equivalent, a set of radiation detectors consisting of ionisation chambers and so-called REM counters is employed. Ionisation chambers are sensitive to all radiation components, whereas REM counters are used to determine separately the neutron component. In this study measurements were carried out in a high-energy reference field at CERN to investigate the responses of the different detectors to a mixed radiation field under controlled conditions. In addition, the field and the corresponding ambient dose equivalents were simulated with FLUKA Monte Carlo calculations. The outcome of these studies determines the choice of radiation detectors for LHC and serves as a basis for a future certification of these instruments. In addition, the results will contribute to a global quality assurance system for CERN’s radiation protection instrumentation.