The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
H Ing - One of the best experts on this subject based on the ideXlab platform.
-
Bubble-Detector measurements of neutron radiation in the international space station: ISS-34 to ISS-37
Radiation protection dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, M. R. Koslowksy, Vyacheslav ShurshakovAbstract:Bubble Detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of Detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.
-
Response of the Bubble Detector to neutrons of various energies.
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, Martin R. KoslowskyAbstract:A series of Monte-Carlo simulations has been performed in order to investigate the response of the Bubble Detector to monoenergetic neutrons of various energies. The work was driven by the need to better understand the energy dependence of the Detector for applications in space, where the neutron spectrum has a significant component with energy of >20 MeV. The response to neutrons in the range of a few keV to 500 MeV has been calculated, and good agreement between the simulations and experimental data is demonstrated over the entire energy range.
-
Bubble-Detector measurements in the Russian segment of the International Space Station during 2009–12
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Vyacheslav ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
Measurements of the neutron dose and energy spectrum on the International Space Station during expeditions ISS-16 to ISS-21.
Radiation protection dosimetry, 2012Co-Authors: M. B. Smith, H R Andrews, H Ing, B J Lewis, R. Machrafi, V. Arkhangelsky, Yu Akatov, I Chernykh, N Khoshooniy, I. NikolaevAbstract: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
-
Review of Bubble Detector response characteristics and results from space.
Radiation protection dosimetry, 2011Co-Authors: B J Lewis, H R Andrews, H Ing, M. B. Smith, R. Machrafi, L. Tomi, T. J. Matthews, L. Veloce, Vyacheslav Shurshakov, I. TchernykhAbstract: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.
H R Andrews - One of the best experts on this subject based on the ideXlab platform.
-
Bubble-Detector measurements of neutron radiation in the international space station: ISS-34 to ISS-37
Radiation protection dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, M. R. Koslowksy, Vyacheslav ShurshakovAbstract:Bubble Detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of Detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.
-
Bubble Detector measurements in the russian segment of the international space station during 2009 12
Radiation Protection Dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, H Ing, V A ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
Response of the Bubble Detector to neutrons of various energies.
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, Martin R. KoslowskyAbstract:A series of Monte-Carlo simulations has been performed in order to investigate the response of the Bubble Detector to monoenergetic neutrons of various energies. The work was driven by the need to better understand the energy dependence of the Detector for applications in space, where the neutron spectrum has a significant component with energy of >20 MeV. The response to neutrons in the range of a few keV to 500 MeV has been calculated, and good agreement between the simulations and experimental data is demonstrated over the entire energy range.
-
Bubble-Detector measurements in the Russian segment of the International Space Station during 2009–12
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Vyacheslav ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
measurements of the neutron dose and energy spectrum on the international space station during expeditions iss 16 to iss 21
Radiation Protection Dosimetry, 2013Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Yu Akatov, I Chernykh, N Khoshooniy, R Y RomanenkoAbstract: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.
M. B. Smith - One of the best experts on this subject based on the ideXlab platform.
-
Bubble-Detector measurements of neutron radiation in the international space station: ISS-34 to ISS-37
Radiation protection dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, M. R. Koslowksy, Vyacheslav ShurshakovAbstract:Bubble Detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of Detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.
-
Bubble Detector measurements in the russian segment of the international space station during 2009 12
Radiation Protection Dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, H Ing, V A ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
Response of the Bubble Detector to neutrons of various energies.
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, Martin R. KoslowskyAbstract:A series of Monte-Carlo simulations has been performed in order to investigate the response of the Bubble Detector to monoenergetic neutrons of various energies. The work was driven by the need to better understand the energy dependence of the Detector for applications in space, where the neutron spectrum has a significant component with energy of >20 MeV. The response to neutrons in the range of a few keV to 500 MeV has been calculated, and good agreement between the simulations and experimental data is demonstrated over the entire energy range.
-
Bubble-Detector measurements in the Russian segment of the International Space Station during 2009–12
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Vyacheslav ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
measurements of the neutron dose and energy spectrum on the international space station during expeditions iss 16 to iss 21
Radiation Protection Dosimetry, 2013Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Yu Akatov, I Chernykh, N Khoshooniy, R Y RomanenkoAbstract: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.
John Kildea - One of the best experts on this subject based on the ideXlab platform.
-
measuring neutron spectra in radiotherapy using the nested neutron spectrometer
Medical Physics, 2015Co-Authors: R Maglieri, Angel Licea, Michael D C Evans, J Seuntjens, John KildeaAbstract:Purpose: Out-of-field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and an occupational risk to personnel during radiotherapy. To quantify neutron production, in-room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils and TLDs. In this work, a recently developed active Detector, the nested neutron spectrometer (NNS), was tested in radiotherapy bunkers. Methods: The NNS is designed for easy handling and is more practical than the traditional BSS. Operated in current-mode, the problem of pulse pileup due to high dose-rates is overcome by measuring current, similar to an ionization chamber. In a bunker housing a Varian Clinac 21EX, the performance of the NNS was evaluated in terms of reproducibility, linearity, and dose-rate effects. Using a custom maximum-likelihood expectation–maximization algorithm, measured neutron spectra at various locations inside the bunker were then compared to Monte Carlo simulations of an identical setup. In terms of dose, neutron ambient dose equivalents were calculated from the measured spectra and compared to Bubble Detector neutron dose equivalent measurements. Results: The NNS-measured spectra for neutrons at various locations in a treatment room were found to be consistent with expectations for both relative shape and absolute magnitude. Neutron fluence-rate decreased with distance from the source and the shape of the spectrum changed from a dominant fast neutron peak near the Linac head to a dominant thermal neutron peak in the moderating conditions of the maze. Monte Carlo data and NNS-measured spectra agreed within 30% at all locations except in the maze where the deviation was a maximum of 40%. Neutron ambient dose equivalents calculated from the authors’ measured spectra were consistent (one standard deviation) with Bubble Detector measurements in the treatment room. Conclusions: The NNS may be used to reliably measure the neutron spectrum of a radiotherapy beam in less than 1 h, including setup and data unfolding. This work thus represents a new, fast, and practical method for neutron spectral measurements in radiotherapy.
-
sci fri pm dosimetry 02 a nested neutron spectrometer to measure neutron spectra in radiotherapy
Medical Physics, 2014Co-Authors: R Maglieri, Angel Licea, J Seuntjens, John KildeaAbstract:During high-energy radiotherapy treatments, neutrons are produced in the head of the linac through photonuclear interactions. This has been a concern for many years as photoneutrons contribute to the accepted, yet unwanted, out-of-field doses that pose an iatrogenic risk to patients and an occupational risk to personnel. Presently, in-room neutron measurements are difficult and time-consuming and have traditionally been carried out using Bonner spheres with activation foils and TLDs. In this work, a new Detector, the Nested Neutron Spectrometer (NNS) is tested for use in radiotherapy bunkers. The NNS is designed for easy handling and is more practical than the traditional Bonner spheres. The NNS, operated in current mode, was used to measure the dose equivalent, average energy and energy spectrum at several positions in a radiotherapy bunker. The average energy and spectra were compared to Monte Carlo simulations while the dose equivalent was compared to Bubble Detector measurements. The average energies, as measured by the NNS and Monte Carlo simulations, differed by approximately 30% across the bunker. Measurements of the dose equivalent using the NNS and the Bubble Detectors agreed within 50% in the maze and less than 10% close to the linac head. Apart from some discrepancies at thermal energies, we also found reasonable agreement between NNS-measured and Monte Carlo-simulated spectra at a number of locations within our radiotherapy bunker. Our results demonstrate that the NNS is a suitable Detector to be used in high dose-rate radiotherapy environments.
R. Machrafi - One of the best experts on this subject based on the ideXlab platform.
-
Comparison of the space Bubble Detector response to space-like neutron spectra and high energy protons
Acta Astronautica, 2018Co-Authors: A. Miller, R. Machrafi, Eric Benton, Hisashi Kitamura, Satoshi KodairaAbstract:Abstract To compare the response to high energy neutrons and protons of the space Bubble Detectors in use aboard the International Space Station (ISS), three series of experiments were conducted with high energy protons and neutrons. The first series of experiments was conducted with high-energy neutrons in the energy range expected for neutrons encountered during space flight (0.6–800 MeV) at the Los Alamos Neutron Science Center (LANSCE) using the spallation neutron source. The second series was conducted with high energy protons from 30 to 70 MeV using the cyclotron at the National Institute of Radiological Science NIRS in Japan, and the third series of experiments was performed with high energy protons from 60 to 230 MeV at the ProCure proton therapy facility, Oklahoma, USA. The Bubble Detectors were exposed to different fluences in different experiments and the number of Bubbles was counted using a Bubble Detector reader. The proton response of the Bubble Detector (sensitivity), as a function of energy, was determined and compared to the neutron sensitivity. In addition, to adjust the neutron sensitivity of the Bubble Detector determined in an AmBe field, a calibration factor was obtained for space applications.
-
Bubble-Detector measurements of neutron radiation in the international space station: ISS-34 to ISS-37
Radiation protection dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, M. R. Koslowksy, Vyacheslav ShurshakovAbstract:Bubble Detectors have been used to characterise the neutron dose and energy spectrum in several modules of the International Space Station (ISS) as part of an ongoing radiation survey. A series of experiments was performed during the ISS-34, ISS-35, ISS-36 and ISS-37 missions between December 2012 and October 2013. The Radi-N2 experiment, a repeat of the 2009 Radi-N investigation, included measurements in four modules of the US orbital segment: Columbus, the Japanese experiment module, the US laboratory and Node 2. The Radi-N2 dose and spectral measurements are not significantly different from the Radi-N results collected in the same ISS locations, despite the large difference in solar activity between 2009 and 2013. Parallel experiments using a second set of Detectors in the Russian segment of the ISS included the first characterisation of the neutron spectrum inside the tissue-equivalent Matroshka-R phantom. These data suggest that the dose inside the phantom is ∼70% of the dose at its surface, while the spectrum inside the phantom contains a larger fraction of high-energy neutrons than the spectrum outside the phantom. The phantom results are supported by Monte Carlo simulations that provide good agreement with the empirical data.
-
Bubble Detector measurements in the russian segment of the international space station during 2009 12
Radiation Protection Dosimetry, 2015Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, H Ing, V A ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
Bubble-Detector measurements in the Russian segment of the International Space Station during 2009–12
Radiation protection dosimetry, 2014Co-Authors: M. B. Smith, H R Andrews, H Ing, R. Machrafi, S. Khulapko, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Vyacheslav ShurshakovAbstract:Measurements using Bubble Detectors have been performed in order to characterise the neutron dose and energy spectrum in the Russian segment of the International Space Station (ISS). Experiments using Bubble dosemeters and a Bubble-Detector spectrometer, a set of six Detectors with different energy thresholds that is used to determine the neutron spectrum, were performed during the ISS-22 (2009) to ISS-33 (2012) missions. The spectrometric measurements are in good agreement with earlier data, exhibiting expected features of the neutron energy spectrum in space. Experiments using a hydrogenous radiation shield show that the neutron dose can be reduced by shielding, with a reduction similar to that determined in earlier measurements using Bubble Detectors. The Bubble-Detector data are compared with measurements performed on the ISS using other instruments and are correlated with potential influencing factors such as the ISS altitude and the solar activity. Surprisingly, these influences do not seem to have a strong effect on the neutron dose or energy spectrum inside the ISS.
-
measurements of the neutron dose and energy spectrum on the international space station during expeditions iss 16 to iss 21
Radiation Protection Dosimetry, 2013Co-Authors: M. B. Smith, H R Andrews, R. Machrafi, V. Arkhangelsky, B. J. Lewis, I. Nikolaev, Yu Akatov, I Chernykh, N Khoshooniy, R Y RomanenkoAbstract: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.
