Mission Statement:
The aim of the ¿DOSIS ¿ 3D¿ experiment is the determination of the radiation environment and its variation onboard the International Space Station (ISS) using various active and passive radiation detector systems, thereby aiming for a concise three dimensional (3D) dose distribution map including all the segments of the ISS.
Objectives:
Besides the effects of the microgravity environment, and the psychological and psychosocial problems encountered in confined spaces, radiation is the main health detriment for long duration human space missions. The radiation environment encountered in space differs in nature from that on earth, consisting mostly of high energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones encountered on earth for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station ISS is therefore needed. As stated in the ¿Mission Statement¿ the objective of the ¿DOSIS 3-D¿ proposal is the reliable characterization of the radiation environment by means of radiation field parameters ¿ such as absorbed dose, linear energy spectra (LET) and biologically relevant dose equivalent ¿ in all parts of the International Space Station. This will include data from various active and passive radiation detector systems currently applied onboard the ISS. The thereby achieved dosimetry database will constitute essential information for the application of radiation protection standards for human spaceflight and for any radiation-susceptible experiment in space. In addition, the measurements will contribute to the understanding of radiation transport through matter and enhance the understanding of the radiation field characteristics e.g. composition and anisotropy.
The objective will be achieved at first hand by applying and combining data from passive radiation detector systems, consisting of thermoluminescence (TLD) and plastic nuclear track detectors (PNTD) able to provide absorbed dose, LET spectra and dose equivalent information. To achieve the three dimensional (3D) dose distribution within the ISS the ¿DOSIS ¿ 3D¿ experiment will not only use data from their own detector systems, but also TLD and PNTD data provided by JAXA (PADLES), NASA (RAM) and IBMP (PILLE) based on their currently applied area monitoring devices.
Further on it is foreseen to use data from active radiation detector systems already onboard the ISS namely the two DOSTELs (as part of the DOSIS experiment in Columbus), the ALTEINO (in the Russian module), the TEPC (in the US module) and the Russian DB-8 detectors (in the Russian part of the station) to gain not only absorbed dose but also LET spectra, charge distribution spectra and dose equivalent data in real time for a better concise radiation field picture. The different systems allow for in-flight cross-calibration of measurements at different shielding configurations. This is absolutely necessary when recognising that the comparison of available data is often not possible due to not well known angular response of the detector systems combined with unknown angular incidence of radiations and only approximate knowledge of shielding distributions. Based on all these data from the active and passive radiation detectors it is foreseen to build up an interactive database serving the scientific community and holding essential information for the application of radiation protection standards for human spaceflight and for any radiation-susceptible experiment in space. An extensive ground intercalibration program, for a better understanding of the properties of the applied radiation detector systems will be applied as an indispensable part of the work with contributions from all participating investigators.
