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Research Containing: Radiation Dosage

Dose distribution in the Russian Segment of the International Space Station

by on 9 June 2015in Technology Development & Demonstration No comment

Absorbed dose and average linear energy transfer (LET) were assessed by means of (7)LiF:Mg,Ti (TLD-700) thermoluminescent (TL) detectors for different panels on-board the Russian Segment of the International Space Station in the timeframe between March and November 2002 (233 d). A technique is presented to correct the measured absorbed dose values for TL efficiency in the radiation climate on-board the spacecraft. Average LET is determined from the high-temperature TL emission in the TLD-700 glow curve and used as a parameter in the TL efficiency correction. Depending on the shielding distribution, the efficiency-corrected absorbed dose varies between 154 +/- 5 microGy d(-1) in panel no. 327 (core block ceiling) and 191 +/- 3 microGy d(-1) in panel no. 110 (core block central axis, floor). The experimental data are compared with the model calculations by using detailed shielding distributions and orbit parameters as inputs.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/16606660

MOSFET dosimetry mission inside the ISS as part of the Matroshka-R experiment

by on 9 June 2015in Technology Development & Demonstration No comment

Radiation measurements of surface and deep organ doses were performed aboard the International Space Station, for the period of January 2006 to April 2007, using a MOSFET dosimetry system combined with the Matroshka-R spherical phantom. The averaged internal and surface dose rates are found to be 0.19 and 0.29 mGy d(-1), respectively. The levels of radiation dose to blood-forming organs (BFO) and to surface organs are compared with recommended safe limits. The maximum measured BFO dose has an average dose rate of 0.23 mGy d(-1) (84 mGy y(-1)), corresponding to 44 % of the recommended annual limit of 0.5 Sv, for a space radiation quality factor of 2.6. The annual surface dose is found to be higher at 126 mGy, corresponding to 16 % of the eye dose limit and to 11 % of the skin dose limit. Doses calculated using the Spenvis software showed deviations of up to 37 % from measurements.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/19933696

Absorbed dose of secondary neutrons from galactic cosmic rays inside the International Space Station

by on 9 June 2015in Technology Development & Demonstration No comment

In this paper, we present the results of Monte-Carlo simulations of the flux and energy spectra of neutrons generated as a result of galactic cosmic ray proton interactions with the material of International Space Station (ISS) inside Zvezda Service Module, the Airlock between Russian and USA segments and one of Russian Research Modules for a full configuration of ISS. Calculations were made for ISS orbit for the energy ranges <10 and >10 MeV for both maximum and minimum of solar activity. To test the accuracy of the calculations the same simulations were made for MIR orbital station and for CORONAS-I satellite and compared with the results of measurements. Calculated and measured fluxes are in reasonable agreement.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/15881787

Measurements of the neutron dose and energy spectrum on the International Space Station during expeditions ISS-16 to ISS-21

by on 9 June 2015in Physical Sciences No comment

As part of the international Matroshka-R and Radi-N experiments, bubble detectors have been used on board the ISS in order to characterise the neutron dose and the energy spectrum of neutrons. Experiments using bubble dosemeters inside a tissue-equivalent phantom were performed during the ISS-16, ISS-18 and ISS-19 expeditions. During the ISS-20 and ISS-21 missions, the bubble dosemeters were supplemented by a bubble-detector spectrometer, a set of six detectors that was used to determine the neutron energy spectrum at various locations inside the ISS. The temperature-compensated spectrometer set used is the first to be developed specifically for space applications and its development is described in this paper. Results of the dose measurements indicate that the dose received at two different depths inside the phantom is not significantly different, suggesting that bubble detectors worn by a person provide an accurate reading of the dose received inside the body. The energy spectra measured using the spectrometer are in good agreement with previous measurements and do not show a strong dependence on the precise location inside the station. To aid the understanding of the bubble-detector response to charged particles in the space environment, calculations have been performed using a Monte-Carlo code, together with data collected on the ISS. These calculations indicate that charged particles contribute <2% to the bubble count on the ISS, and can therefore be considered as negligible for bubble-detector measurements in space.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/22826353

Cosmic ray detection on the ISS by a 3 axes track etch detector stack and the complementary calibration studies

by on 9 June 2015in Physical Sciences No comment

The complex radiation field inside the International Space Station (ISS) as well as the dose received by its crew was studied for several years in the BRADOS ( 1 – 5 ) projects organized by the Institute for Biomedical Problems (IBMP, Moscow) with the participation of different laboratories. The results of the measurements performed during the BRADOS-5 project by a 3 axes solid state nuclear track detector (SSNTD) stack as LET spectra and dose values are presented. According to the results, no remarkable directional dependence could be observed in the radiation field. The averaged absorbed dose rate and dose equivalent rate values above ∼ 12 keV μ m – 1 were 27.0 ± 1.6 μ Gy d – 1 and 211.4 ± 14.4 μ Sv d – 1 , respectively, resulting in an averaged quality factor of 7.9 ± 0.1 .

Related URLs:
http://www.sciencedirect.com/science/article/pii/S1350448708000656

Study of radiation conditions onboard the International space station by means of the Liulin-5 dosimeter

by on 9 June 2015in Physical Sciences No comment

For estimating radiation risk in space flights it is necessary to determine radiation dose obtained by critical organs of a human body. For this purpose the experiments with human body models are carried out onboard spacecraft. These models represent phantoms equipped with passive and active radiation detectors which measure dose distributions at places of location of critical organs. The dosimetric Liulin-5 telescope is manufactured with using three silicon detectors for studying radiation conditions in the spherical tissue-equivalent phantom on the Russian segment of the International space station (ISS). The purpose of the experiment with Liulin-5 instrument is to study dynamics of the dose rate and particle flux in the phantom, as well as variations of radiation conditions on the ISS over long time intervals depending on a phase of the solar activity cycle, orbital parameters, and presence of solar energetic particles. The Liulin-5 dosimeter measures simultaneously the dose rate and fluxes of charged particles at three depths in the radial channel of the phantom, as well as the linear energy transfer. The paper presents the results of measurements of dose rate and particle fluxes caused by various radiation field components on the ISS during the period from June 2007 till December 2009.

Related URLs:
http://dx.doi.org/10.1134/S0010952512060068

Investigation of dose and flux dynamics in the Liulin-5 dosimeter of the tissue-equivalent phantom onboard the Russian segment of the international space station

by on 9 June 2015in Physical Sciences No comment

Described is the Liulin-5 active dosimetric telescope designed for measurement of the space radiation dose depth-distribution in a human phantom on the Russian Segment of the International Space Station (ISS). The Liulin-5 experiment is a part of the international project MATROSHKA-R on ISS. The MATROSHKA-R project is aimed to study the depth- dose distribution at the sites of critical organs of the human body, using models of human body-anthropomorphic ant spherical tissue-equivalent phantoms. The aim of Liulin-5 experiment is a long term (4–5 years) investigation of the radiation environment dynamics inside the spherical tissue-equivalent phantom, mounted in different compartments. Energy deposition spectra, linear energy transfer spectra, and flux and dose rates for charged particles will be measured simultaneously with near real time resolution at different depths of the phantom by means of three silicon detectors. Data obtained together with data from other active and passive dosimeters will be used to estimate the radiation risk to the crewmembers, which verify the models of radiation environment in low Earth orbit. Presented are the test results of the prototype unit. Liulin-5 will be flown on the ISS in the year 2003.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0273117702009523

Review of bubble detector response characteristics and results from space

by on 9 June 2015in Physical Sciences No comment

A passive neutron-bubble dosemeter (BD), developed by Bubble Technology Industries, has been used for space applications. Both the bubble detector-personal neutron dosemeter and bubble detector spectrometer have been studied at ground-based facilities in order to characterise their response due to neutrons, heavy ion particles and protons. This technology was first used during the Canadian-Russian collaboration aboard the Russian satellite BION-9, and subsequently on other space missions, including later BION satellites, the space transportation system, Russian MIR space station and International Space Station. This paper provides an overview of the experiments that have been performed for both ground-based and space studies in an effort to characterise the response of these detectors to various particle types in low earth orbit and presents results from the various space investigations.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/21890528

Neutron dose study with bubble detectors aboard the International Space Station as part of the Matroshka-R experiment

by on 9 June 2015in Physical Sciences No comment

As part of the Matroshka-R experiments, a spherical phantom and space bubble detectors (SBDs) were used on board the International Space Station to characterise the neutron radiation field. Seven experimental sessions with SBDs were carried out during expeditions ISS-13, ISS-14 and ISS-15. The detectors were positioned at various places throughout the Space Station, in order to determine dose variations with location and on/in the phantom in order to establish the relationship between the neutron dose measured externally to the body and the dose received internally. Experimental data on/in the phantom and at different locations are presented.

Related URLs:
http://rpd.oxfordjournals.org/content/133/4/200.abstract
http://rpd.oxfordjournals.org/content/133/4/200

Dose distribution in the depth of the tissue-equivalent ball phantom modeling location of human body critical organs inside the compartments of the International space station

by on 9 June 2015in Physical Sciences No comment

Goal of the investigation is to study and to analyze radiation dose distribution in cosmonaut's body during long-term mission aboard the International space station (ISS). The established patterns of dose distribution under different conditions of the experiment allow simplify evaluation of dose accumulation by spacecrew. Dose from ionizing space radiation was determined with the help of thermoluminescent dosimeters mounted in conditional depths of critical organs in human body modeled in a dosimetric device, i.e.–a ball-like tissue-equivalent phantom designed and manufactured in Russia for international space experiment Matreshka-R. The article reports experimental data disclosing the character and levels of exposure to ionizing radiation inside the Service module crew quarters during ISS missions 8 and 9 (425 days, 2004-2005) and the docking compartment (SO1) during ISS missions 15 and 16 (285 days, 2007-2008).

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/20120916