The response of various neutron dosemeters in applied radiation protection at high-energy heavy-ion-accelerators

The response of several rem-counters of the Andersson-Braun type with respect to the ambient dose equivalent H*(10) is investigated. Therefore a 241Am-Be neutron source as well as the high-energy reference field at CERN is employed. Two of the tested rem-counters are equipped with an additional lead absorber, in order to achieve a better response for high-energy neutrons. The response of these extended range rem-counters to neutrons from the 241Am-Be test source in relation to that to neutrons from the reference field is 1.1 and 0.91. For the conventional rem-counters one obtains ratios between 1,5 and 1,8. Hence a radiation monitor calibrated to ambient dose equivalent with the help of 241Am-Be neutron source may exhibit values at high-energy particle accelerators which are only 55% to 66% of the actual dose. From parallel investigations with the tissue-equivalent proportional counter HANDI the distribution of the dose in lineal energy is determined. Out of this spectra the dose equivalent can be calculated with the help of the Q(L) function. Compared to the ambient dose equivalent H*(10) one obtains values for the dose equivalent which are 28% higher for the 241Am-Be test source and 15% higher for the reference field. (orig.)