The experiment 'Dosimetric Mapping' conducted as part of the science program of NASA's Human Research Facility (HRF) between March and August 2001 was designed to measure integrated total absorbed doses (ionising radiation and neutrons), heavy ion fluxes and its energy, mass and linear energy transfer (LET) spectra, time-dependent count rates of charged particles and their corresponding dose rates at different locations inside the US Lab at the International Space Station. Owing to the variety of particles and energies, a dosimetry package consisting of thermoluminescence dosemeter (TLD) chips and nuclear track detectors with and without converters (NTDPs), a silicon dosimetry telescope (DOSTEL), four mobile silicon detector units (MDUs) and a TLD reader unit (PILLE) with 12 TLD bulbs as dosemeters was used. Dose rates of the ionising part of the radiation field measured with TLD bulbs applying the PILLE readout system at different locations varied between 153 and 231 microGy d(-1). The dose rate received by the active devices fits excellent to the TLD measurements and is significantly lower compared with measurements for the Shuttle (STS) to MIR missions. The comparison of the absorbed doses from passive and active devices showed an agreement within +/- 10%. The DOSTEL measurements in the HRF location yielded a mean dose equivalent rate of 535 microSv d(-1). DOSTEL measurements were also obtained during the Solar Particle Event on 15 April 2001.

Photoneutron production was investigated on Siemens KD 2 and Varian Clinac accelerators operating in the 6-18 MV range. Neutron dose equivalent rates were measured on the surface of a water phantom at the isocenter of the accelerators and also inside the phantom at depths of 1, 5, and 10 cm and off-axis distances of 0, 20, and 50 cm. Superheated drop detectors based on dichlorofluoromethane and etched-track detectors with boronated converters were employed in this study. The energy response of these detectors permits a direct measurement of dose equivalent without prior knowledge of the neutron energy spectra. Dose equivalent rates were assessed using the Q(L) relationship from ICRP publication 60, as well as using earlier data from ICRP publication 21. This permitted both a comparison with previously published data and an assessment of the impact of the recent ICRP recommendations--which were found to increase the dose equivalent levels by about 30%. In addition, the depth corresponding to 50% of maximum dose equivalent, dH50, was determined along the central axis of the beams and at 50 cm off-axis. Monte Carlo neutron transport calculations were performed to determine the depth-dose equivalent distributions in a phantom irradiated with monoenergetic neutrons. Effective energies of the photoneutron spectra were then estimated by comparing our measured dH50 values to those calculated for monoenergetic neutrons. It was found that the effective photoneutron energy is 1.8-2.1 MeV within the 10-18 MV x-ray beams, and it is 0.5-0.8 MeV for photoneutrons transmitted through the accelerator head. Data from this work cover most of the x-ray beam energies in clinical use and permit an assessment of integral dose values as well as specific organ doses to a radiotherapy patient.

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Mainly based on data for local susceptibilities and 3d spin rates of dilute Fe ions in many metals, we conclude that the existence and stability of Fe, Co, and Ni moments in Cu, Ag, Au, and certain transition-metal hosts are governed by impurity-3*/ host-d electron interactions. As the leading contribution to moment stability we propose ferromagnetic-3d host-*/ exchanges which in certain hosts successfully suppress spin fluctuations arising from antiferromagnetic d-sp exchanges. All host-dependent trends of moment stability of Mn, Fe, Co, and Ni ions in metals are consistent with our proposal.

7Swedish Radiation Protection Authority, SE-171-16 Stockholm, SwedenThe paper presents the main conclusions and recommendations derived from the EVIDOS project, which is supported by the European Commission within the 5th Framework Programme. EVIDOS aims at evaluating state of the art neutron dosimetry techniques in representative workplaces of the nuclear industry with complex mixed neutron-photon radiation fields. This analysis complements a series of individual papers which present detailed results and it summarises the main findings from a practical point of view. Conclusions and recommendations are given concerning characterisation of radiation fields, methods to derive radiation protection quantities and dosemeter results.