International space station: A testbed for experimental and computational dosimetry (original) (raw)
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Space radiation measurements on-board ISS--the DOSMAP experiment
Radiation Protection Dosimetry, 2005
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 lGy d À1 . 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 AE10%. The DOSTEL measurements in the HRF location yielded a mean dose equivalent rate of 535 lSv d À1 . DOSTEL measurements were also obtained during the Solar Particle
Radiation survey in the International Space Station
Journal of Space Weather and Space Climate, 2015
The project ALTEA-shield/survey is part of an European Space Agency (ESA)-ILSRA (International Life Science Research Announcement) program and provides a detailed study of the International Space Station (ISS) (USLab and partly Columbus) radiation environment. The experiment spans over 2 years, from September 20, 2010 to September 30, 2012, for a total of about 1.5 years of effective measurements. The ALTEA detector system measures all heavy ions above helium and, to a limited extent, hydrogen and helium (respectively, in 25 Mev-45 MeV and 25 MeV/n-250 MeV/n energy windows) while tracking every individual particle. It measures independently the radiation along the three ISS coordinate axes. The data presented consist of flux, dose, and dose equivalent over the time of investigation, at the different surveyed locations. Data are selected from the different geographic regions (low and high latitudes and South Atlantic Anomaly, SAA). Even with a limited acceptance window for the proton contribution, the flux/dose/dose equivalent results as well as the radiation spectra provide information on how the radiation risks change in the different surveyed sites. The large changes in radiation environment found among the measured sites, due to the different shield/mass distribution, require a detailed Computer-Aided Design (CAD) model to be used together with these measurements for the validation of radiation models in space habitats. Altitude also affects measured radiation, especially in the SAA. In the period of measurements, the altitude (averaged over each minute) ranged from 339 km to 447 km. Measurements show the significant shielding effect of the ISS truss, responsible for a consistent amount of reduction in dose equivalent (and so in radiation quality). Measured Galactic Cosmic Ray (GCR) dose rates at high latitude range from 0.354 ± 0.002 nGy/s to 0.770 ± 0.006 nGy/s while dose equivalent from 1.21 ± 0.04 nSv/s to 6.05 ± 0.09 nSv/s. The radiation variation over the SAA is studied. Even with the reduced proton sensitivity, the high day-by-day variability, as well as the strong altitude dependence is clearly observed. The ability of filtering out this contribution from the data is presented as a tool to construct a radiation data set well mimicking deep space radiation, useful for model validations and improvements.
Journal of Space Weather and Space Climate, 2016
The radiation environment encountered in space differs in nature from that on Earth, consisting mostly of highly energetic ions from protons up to iron, resulting in radiation levels far exceeding the ones present on Earth for occupational radiation workers. Since the beginning of the space era, the radiation exposure during space missions has been monitored with various active and passive radiation instruments. Also onboard the International Space Station (ISS), a number of area monitoring devices provide data related to the spatial and temporal variation of the radiation field in and outside the ISS. The aim of the DOSIS (2009-2011) and the DOSIS 3D (2012-ongoing) experiments was and is to measure the radiation environment within the European Columbus Laboratory of the ISS. These measurements are, on the one hand, performed with passive radiation detectors mounted at 11 locations within Columbus for the determination of the spatial distribution of the radiation field parameters and, on the other, with two active radiation detectors mounted at a fixed position inside Columbus for the determination of the temporal variation of the radiation field parameters. Data measured with passive radiation detectors showed that the absorbed dose values inside the Columbus Laboratory follow a pattern, based on the local shielding configuration of the radiation detectors, with minimum dose values observed in the year 2010 of 195-270 lGy/day and maximum values observed in the year 2012 with values ranging from 260 to 360 lGy/day. The absorbed dose is modulated by (a) the variation in solar activity and (b) the changes in ISS altitude.
Journal of Space Weather and Space Climate, 2017
The natural radiation environment in Low Earth Orbit (LEO) differs significantly in composition and energy from that found on Earth. The space radiation field consists of high energetic protons and heavier ions from Galactic Cosmic Radiation (GCR), as well as of protons and electrons trapped in the Earth's radiation belts (Van Allen belts). Protons and some heavier particles ejected in occasional Solar Particle Events (SPEs) might in addition contribute to the radiation exposure in LEO. All sources of radiation are modulated by the solar cycle. During solar maximum conditions SPEs occur more frequently with higher particle intensities. Since the radiation exposure in LEO exceeds exposure limits for radiation workers on Earth, the radiation exposure in space has been recognized as a main health concern for humans in space missions from the beginning of the space age on. Monitoring of the radiation environment is therefore an inevitable task in human spaceflight. Since mission profiles are always different and each spacecraft provides different shielding distributions, modifying the radiation environment measurements needs to be done for each mission. The experiments ''Dose Distribution within the ISS (DOSIS)'' (2009-2011) and ''Dose Distribution within the ISS 3D (DOSIS 3D)'' (2012-onwards) onboard the Columbus Laboratory of the International Space Station (ISS) use a detector suite consisting of two silicon detector telescopes (DOSimetry TELescope = DOSTEL) and passive radiation detector packages (PDP) and are designed for the determination of the temporal and spatial variation of the radiation environment. With the DOSTEL instruments' changes of the radiation composition and the related exposure levels in dependence of the solar cycle, the altitude of the ISS and the influence of attitude changes of the ISS during Space Shuttle dockings inside the Columbus Laboratory have been monitored. The absorbed doses measured at the end of May 2016 reached up to 286 lGy/day with dose equivalent values of 647 lSv/day.
Advances in Space Research, 2014
The International Space Station Cosmic Radiation Exposure Model (ISSCREM) has been developed as a possible tool for use in radiation mission planning as based on operational data collected with a tissue equivalent proportional counter (TEPC) aboard the ISS since 2000. It is able to reproduce the observed trapped radiation and galactic cosmic radiation (GCR) contributions to the total dose equivalent to within ±20% and ±10%, respectively, as would be measured by the onboard TEPC at the Zvezda Service Module panel 327 (SM-327). Furthermore, when these contributions are combined, the total dose equivalent that would be measured at this location is estimated to within ±10%. The models incorporated into ISSCREM correlate the GCR dose equivalent rate to the cutoff rigidity magnetic shielding parameter and the trapped radiation dose equivalent rate to atmospheric density inside the South Atlantic Anomaly. The GCR dose equivalent rate is found to vary minimally with altitude and TEPC module location however, due to the statistics and data available, the trapped radiation model could only be developed for the TEPC located at SM-327. Evidence of the variation in trapped radiation dose with detector orientation and the East-West asymmetry were observed at this location.
Advances in Space …, 2004
The Atominstitute of the Austrian Universities has conducted various space research missions in the last 12 years in cooperation with the Institute for Biomedical Problems in Moscow. They dealt with the exact determination of the radiation hazards for cosmonauts and the development of precise measurement devices. Special emphasis will be laid on the last experiment on space station MIR the goal of which was the determination of the depth distribution of absorbed dose and dose equivalent in a water filled Phantom. The first results from dose measurements onboard the International Space Station (ISS) will also be discussed. The spherical Phantom with a diameter of 35 cm was developed at the Institute for Biomedical Problems and had 4 channels where dosemeters can be exposed in different depths. The exposure period covered the timeframe from May 1997 to February 1999. Thermoluminescent dosemeters (TLDs) were exposed inside the Phantom, either parallel or perpendicular to the hull of the spacecraft. For the evaluation of the linear energy transfer (LET), the high temperature ratio (HTR) method was applied. Based on this method a mean quality factor and, subsequently, the dose equivalent is calculated according to the Q(LET 1 ) relationship proposed in ICRP 26. An increased contribution of neutrons could be detected inside the Phantom. However the total dose equivalent did not increase over the depth of the Phantom. As the first Austrian measurements on the ISS dosemeter packages were exposed for 248 days, starting in February 2001 at six different locations onboard the ISS. The Austrian dosemeter sets for this first exposure on the ISS contained five different kinds of passive thermoluminescent dosemeters. First results showed a position dependent absorbed dose rate at the ISS.
Radiation Risk Predictions for Space Station \u3ci\u3eFreedom \u3c/i\u3eOrbits
1991
Risk-assessment calculations are presented for the preliminary proposed solar minimum and solar maximum orbits for Space Station Freedom (SSF). Integral linear energy transfer (LET) fluence spectra are calculated for the trapped-proton and galactic cosmic ray (GCR) environments. Organ-dose calculations are discussed using the Computerized Anatomical Man model. The cellular track model of Katz is applied to calculate cell survival, transformation, and mutation rates for various aluminum shields. Comparisons between relative biological effectiveness (RBE) and quality factors (QF) for SSF orbits are made, and fluence-dependent effects are discussed
Journal of Physics G: Nuclear and Particle Physics, 2014
In this work we present data on linear energy transfer (LET), dose and dose equivalent rates from different locations of the Russian part of the International Space Station (ISS) measured by the Sileye-3/Alteino detector. Data were taken as part of the ESA ALTCRISS project from late 2005 through 2007. The LET rate data shows a heavy-ion (LET >50 keV/μm) anisotropy. From the heavy-ion LET rate in the Zvezda service module we find ISS y(Starboard) and zˆ(Nadir) to be about 10-15 times higher than in x (Forward). The situation is similar for dose and dose equivalent rates, ranging from 25-40 μGy d −1 in x to about 75 μGy d −1 in zˆ, whereas for the dose equivalent the rate peaks in yˆwith around 470 μSv d −1. The heavy-ion anisotropy confirms what has been reported by the ALTEA collaboration. Measurements using two sets of passive detectors, DLR-TLDs and PADLES (TLD+CR-39), have also been performed in conjunction with Alteino measurements, both shielded and unshielded. The passive detectors register a dose rate about 3-5 times as high as Alteino, 260-280 μGy d −1 for PADLES and 200-260 μGy d −1
Simulations of the radiation environment at ISS altitudes
Acta Astronautica, 2009
In order to evaluate and simulate the response of detectors, for measurements of radiation environment inside and outside the International Space Station (ISS), a model for the outside space radiation environment at the altitudes of ISS is required. This estimation can be performed by using e.g. one of the two web-based model packages: CREME96 (Cosmic Ray Effects on Micro Electronics) and SPENVIS (the SPace ENVironment Information System). The main goal of this work is to compare and evaluate these web interfaces and the results given in order to understand how these will influence the simulations of experiments on the ISS.