Response calculations for silicon-based direct-reading dosimeters for use at the international space station (ISS) M. Luszik-Bhadra a, * , P. Beck b , T. Berger c , A. Jaksic d , M. Latocha b , S. Rollet b , M. Vuotila e , A. Zechner b , G. Reitz c a Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany b Austrian Institute of Technology, Donau-City-Straße 1, A-1220 Vienna, Austria c German Aerospace Center, DLR, Linder Hoehe, D-51147 Cologne, Germany d Tyndall National Institute, Lee Maltings, Cork, Ireland e MirionTechnologies (RADOS) Oy, Mustionkatu 2, FI-20101 Turku, Finland article info Article history: Received 13 November 2009 Received in revised form 24 August 2010 Accepted 26 August 2010 Keywords: ISS Silicon detectors TEPC FLUKA GEANT4 PHITS abstract In 2007, the European Space Agency (ESA) initiated the development of European Crew Personal Active Dosimeters. The hardware development objective is to produce an active personal dosimeter which shows absorbed dose and dose equivalent spectra similar to a Tissue Equivalent Proportional Counter (TEPC), but which is based on more robust silicon detector devices. Several detector/dosimeter components have been investigated e by computer simulations e for their performance in the radiation field at the ISS position. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Exposure monitoring for Astronauts by active personal dosim- eters has not yet been performed onboard of the ISS despite a vast field of radiation measurements having been conducted. The present concept is the first attempt to equip crew members in the near future with an active personal dosimeter. The passive radiation personal dosimeter packages currently used at ISS consist of TLDs (Thermoluminescence Dosimeters) and NTDs (Nuclear Track Detectors). The combination of these two passive systems enables the determination of the absorbed dose, the measurement of LET (Linear Energy Transfer) spectra, and e by applying the Q (Quality factor) versus LET relationship as based on ICRP 60 recommendations (ICRP, 1991) e the evaluation of dose equivalent (Straube et al., 2010). However, these detectors are evaluated on Earth; this evaluation is usually performed several weeks or even months after the exposure. The only active dosimeter at the ISS providing a warning in case of high dose rates is a TEPC (Tissue Equivalent Proportional Counter) operated by NASA which can be transported to different positions inside the ISS. Measurements with the dosimetry telescope (DOSTEL) show that the dose equivalent rate strongly increases up to about two orders of magnitude (Reitz et al., 2005), when the ISS passes through the SAA (South Atlantic Anomaly). During such a pass a similar integrated dose as originating from GCR (Galactic Cosmic Ray) radiation during the whole day is obtained within a few minutes from protons trapped by the Earth’s magnetic field (inner Van Allen radiation belts). Astronauts wearing an active personal dosimeter can choose a better shielded position inside the ISS for this short time and can avoid part of the exposure. Passive TLD/CR- 39 devices distributed at different positions inside the ISS showed a variation of dose equivalent by about 50% (Reitz et al., 2005; Zhou et al., 2007). In addition, active personal dosimeters are highly desirable to directly determine the dose equivalent in case of EVAs (Extra Vehicular Activities) and manned missions (e.g. to the Moon or Mars). In 2007, the European Space Agency (ESA) initiated the devel- opment of European Crew Personal Active Dosimeters with a consortium consisting of Physikalisch-Technische Bundesanstalt (PTB), Mirion Technologies (RADOS) Oy, Austrian Institute of * Corresponding author. E-mail address: marlies.luszik-bhadra@ptb.de (M. Luszik-Bhadra). Contents lists available at ScienceDirect Radiation Measurements journal homepage: www.elsevier.com/locate/radmeas 1350-4487/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.radmeas.2010.08.026 Radiation Measurements 45 (2010) 1548e1552