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Dynamics, Composition and Origin of the Geomagnetically-Trapped Corpuscular Radiation. ACTA ACUST UNITED AC 2021. [DOI: 10.1017/s0251107x00022331] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Dawn S, Chatterjee S, Chakrabarty S, Mufti S, Bakshi A, Sapra B. Cosmic ray neutron spectrometry and dosimetry at High Altitude Research Laboratory, Gulmarg, Kashmir, India. Radiat Phys Chem Oxf Engl 1993 2021. [DOI: 10.1016/j.radphyschem.2021.109523] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Double beta decay is a very rare nuclear process and, therefore, experiments intended to detect it must be operated deep underground and in ultra-low background conditions. Long-lived radioisotopes produced by the previous exposure of materials to cosmic rays on the Earth’s surface or even underground can become problematic for the required sensitivity. Here, the studies developed to quantify and reduce the activation yields in detectors and materials used in the set-up of these experiments will be reviewed, considering target materials like germanium, tellurium and xenon together with other ones commonly used like copper, lead, stainless steel or argon. Calculations following very different approaches and measurements from irradiation experiments using beams or directly cosmic rays will be considered for relevant radioisotopes. The effect of cosmogenic activation in present and future double beta decay projects based on different types of detectors will be analyzed too.
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Kollmann P, Roussos E, Kotova A, Cooper JF, Mitchell DG, Krupp N, Paranicas C. MeV proton flux predictions near Saturn's D ring. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2015; 120:8586-8602. [PMID: 27812437 PMCID: PMC5066344 DOI: 10.1002/2015ja021621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/11/2015] [Accepted: 09/22/2015] [Indexed: 06/06/2023]
Abstract
Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.
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Affiliation(s)
- P. Kollmann
- The Johns Hopkins UniversityApplied Physics LaboratoryLaurelMarylandUSA
| | - E. Roussos
- Max Planck Institute for Solar System ResearchGöttingenGermany
| | - A. Kotova
- Max Planck Institute for Solar System ResearchGöttingenGermany
- Université Paul Sabatier Toulouse IIIUPS‐OMP, IRAPToulouseFrance
| | - J. F. Cooper
- NASA Goddard Space Flight CenterGreenbeltMarylandUSA
| | - D. G. Mitchell
- The Johns Hopkins UniversityApplied Physics LaboratoryLaurelMarylandUSA
| | - N. Krupp
- Max Planck Institute for Solar System ResearchGöttingenGermany
| | - C. Paranicas
- The Johns Hopkins UniversityApplied Physics LaboratoryLaurelMarylandUSA
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Köhler J, Ehresmann B, Zeitlin C, Wimmer-Schweingruber RF, Hassler DM, Reitz G, Brinza DE, Appel J, Böttcher S, Böhm E, Burmeister S, Guo J, Lohf H, Martin C, Posner A, Rafkin S. Measurements of the neutron spectrum in transit to Mars on the Mars Science Laboratory. LIFE SCIENCES IN SPACE RESEARCH 2015; 5:6-12. [PMID: 26177845 DOI: 10.1016/j.lssr.2015.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 03/16/2015] [Accepted: 03/19/2015] [Indexed: 06/04/2023]
Abstract
The Mars Science Laboratory spacecraft, containing the Curiosity rover, was launched to Mars on 26 November 2011. Although designed for measuring the radiation on the surface of Mars, the Radiation Assessment Detector (RAD) measured the radiation environment inside the spacecraft during most of the 253-day, 560-million-kilometer cruise to Mars. An important factor for determining the biological impact of the radiation environment inside the spacecraft is the specific contribution of neutrons with their high biological effectiveness. We apply an inversion method (based on a maximum-likelihood estimation) to calculate the neutron and gamma spectra from the RAD neutral particle measurements. The measured neutron spectrum (12-436 MeV) translates into a radiation dose rate of 3.8±1.2 μGy/day and a dose equivalent of 19±5 μSv/day. Extrapolating the measured spectrum (0.1-1000 MeV), we find that the total neutron-induced dose rate is 6±2 μGy/day and the dose equivalent rate is 30±10 μSv/day. For a 360 day round-trip from Earth to Mars with comparable shielding, this translates into a neutron induced dose equivalent of about 11±4 mSv.
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Affiliation(s)
- J Köhler
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany.
| | - B Ehresmann
- Southwest Research Institute, Space Science and Engineering Division, Boulder, USA
| | - C Zeitlin
- Southwest Research Institute, Earth, Oceans & Space Department, Durham, NH, USA
| | | | - D M Hassler
- Southwest Research Institute, Space Science and Engineering Division, Boulder, USA
| | - G Reitz
- Aerospace Medicine, Deutsches Zentrum für Luft- und Raumfahrt, Köln, Germany
| | - D E Brinza
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - J Appel
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - S Böttcher
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - E Böhm
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - S Burmeister
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - J Guo
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - H Lohf
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - C Martin
- Institute of Experimental and Applied Physics, Christian-Albrechts-University, Kiel, Germany
| | - A Posner
- NASA Headquarters, Science Mission Directorate, Washington DC, USA
| | - S Rafkin
- Southwest Research Institute, Space Science and Engineering Division, Boulder, USA
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Newkirk LL. Calculation of low-energy neutron flux in the atmosphere by theSnmethod. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz068i007p01825] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lenchek AM, Singer SF. Geomagnetically trapped protons from cosmic-ray albedo neutrons. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz067i004p01263] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hess WN. The radiation belt produced by neutrons leaking out of the atmosphere of the Earth. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz065i010p03107] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Naugle JE, Kniffen DA. Variations of the proton energy spectrum with position in the inner Van Allen Belt. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz068i013p04065] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bame SJ, Conner JP, Brumley FB, Hostetler RL, Green AC. Neutron flux and energy spectrum above the atmosphere. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz068i005p01221] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Lingenfelter RE, Flamm EJ, Canfield EH, Kellman S. High-energy solar neutrons: 2. Flux at the Earth. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz070i017p04087] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Boella G, Antoni GD, Dilworth C, Panetti M, Scarsi L, Intriligator DS. Measurement of the cosmic ray neutron flux at 4.6 billion volts geomagnetic cutoff rigidity. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz070i005p01019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Burnett DS, Lippolt HJ, Wasserburg GJ. The relative isotopic abundance of K40in terrestrial and meteoritic samples. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz071i004p01249] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Yamashita M, Stephens LD, Patterson HW. Cosmic-ray-produced neutrons at ground level: Neutron production rate and flux distribution. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jz071i016p03817] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Heidbreder E, Pinkau K, Reppin C, Schönfelder V. Measurements of the distribution in energy and angle of high-energy neutrons in the lower atmosphere. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja076i013p02905] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Farley TA, Tomassian AD, Chapman MC. Evaluation of the CRAND Source for 10- to 50-Mev trapped protons. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja074i019p04721] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Reedy RC, Arnold JR. Interaction of solar and galactic cosmic-ray particles with the Moon. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja077i004p00537] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Preszler AM, Simnett GM, White RS. Angular distribution and altitude dependence of atmospheric neutrons from 10 to 100 MeV. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja079i001p00017] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Caruso AN. The physics of solid-state neutron detector materials and geometries. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:443201. [PMID: 21403341 DOI: 10.1088/0953-8984/22/44/443201] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Detection of neutrons, at high total efficiency, with greater resolution in kinetic energy, time and/or real-space position, is fundamental to the advance of subfields within nuclear medicine, high-energy physics, non-proliferation of special nuclear materials, astrophysics, structural biology and chemistry, magnetism and nuclear energy. Clever indirect-conversion geometries, interaction/transport calculations and modern processing methods for silicon and gallium arsenide allow for the realization of moderate- to high-efficiency neutron detectors as a result of low defect concentrations, tuned reaction product ranges, enhanced effective omnidirectional cross sections and reduced electron-hole pair recombination from more physically abrupt and electronically engineered interfaces. Conversely, semiconductors with high neutron cross sections and unique transduction mechanisms capable of achieving very high total efficiency are gaining greater recognition despite the relative immaturity of their growth, lithographic processing and electronic structure understanding. This review focuses on advances and challenges in charged-particle-based device geometries, materials and associated mechanisms for direct and indirect transduction of thermal to fast neutrons within the context of application. Calorimetry- and radioluminescence-based intermediate processes in the solid state are not included.
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Affiliation(s)
- A N Caruso
- Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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Janssens-Maenhout G, De Roo F, Janssens W. Contributing to shipping container security: can passive sensors bring a solution? JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2010; 101:95-105. [PMID: 19875213 DOI: 10.1016/j.jenvrad.2009.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 08/10/2009] [Accepted: 09/04/2009] [Indexed: 05/28/2023]
Abstract
Illicit trafficking of fissionable material in container cargoes is recognized as a potential weakness in Nuclear Security. Triggered by the attacks of 11 September 2001, measures were undertaken to enhance maritime security in extension to the Safety Of Life At Sea Convention and in line with the US Container Security Initiatives. Effective detection techniques are needed that allow the inspector to intercept illicit trafficking of nuclear weapons components or components of other nuclear explosive devices. Many security measures focus on active interrogation of the container content by X-ray scan, which might be extended with the newly developed tagged neutron inspection system. Both active interrogation techniques can, with the current huge volume of container traffic, only be applied to a limited number of selected containers. The question arises whether a passive detection technique can offer an alternative solution. This study investigates if containers equipped with a small passive detector will register during transport the neutron irradiation by fissionable material such as plutonium in a measurable way. In practice, 4/5 of the containers are about 1/8 filled with hydrogenous material and undergo a typical 2 months route. For this reference case, it was found that the most compatible passive detector would be an activation foil of iridium. Monte-Carlo simulations showed that for the reference case the activity of a 250 microm thin foil with 6 cm(2) cross-section would register 1.2 Bq when it is irradiated by a significant quantity of Reactor-Grade PuO(2). However this activity drops with almost two orders of magnitude for other fillings and other isotopic compositions and forms of the Pu-source. The procedure of selecting the target material for Pu detection is detailed with the theoretical methods, in order to be useful for other applications. Moreover the value of such additional passive sensors for securing maritime container transport is situated within the global framework of the First, Second and Third Line of Defense against illicit trafficking.
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Affiliation(s)
- G Janssens-Maenhout
- Joint Research Centre Ispra, IES-CCU, Via Fermi 2749, TP. 290, I-21027 Ispra, Italy.
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YAJIMA K, YASUDA H, TAKADA M, SATO T, GOKA T, MATSUMOTO H, NAKAMURA T. Measurements of Cosmic-Ray Neutron Energy Spectra from Thermal to 15 MeV with Bonner Ball Neutron Detector in Aircraft. J NUCL SCI TECHNOL 2010. [DOI: 10.1080/18811248.2010.9711934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Armstrong TW, Chandler KC, Barish J. Calculations of neutron flux spectra induced in the Earth's atmosphere by galactic cosmic rays. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/ja078i016p02715] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Merker M, Light ES, Verschell HJ, Mendell RB, Korff SA. Time dependent worldwide distribution of atmospheric neutrons and of their products: 1. Fast neutron observations. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/ja078i016p02727] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Monk SD, Joyce MJ. The design of a portable cosmic ray three-band neutron detector. RADIATION PROTECTION DOSIMETRY 2007; 123:3-14. [PMID: 16829509 DOI: 10.1093/rpd/ncl074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The design of a portable three-band cosmic-ray neutron detector is reported in this article. This instrument has been designed to characterise cosmic ray neutron fields in the upper atmosphere and in cosmic reference field facilities. The design utilises a spherical moderator with a layer of spallation material covering a central (3)He proportional counter. The instrument incorporates twelve lithium-coated diodes, six on the outside of the polyethylene layer and six placed within the structure. The dimensions, materials and arrangement of these in the instrument have been optimised with MCNPX to provide a compromise between the requirements of portability and spectral response.
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Affiliation(s)
- S D Monk
- Nuclear and Biomedical Engineering Research Group, Department of Engineering, Lancaster University, Lancaster LA1 4YR, UK
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Sheu RJ, Jiang SH. Cosmic-ray-induced neutron spectra and effective dose rates near air/ground and air/water interfaces in Taiwan. HEALTH PHYSICS 2003; 84:92-99. [PMID: 12498521 DOI: 10.1097/00004032-200301000-00008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ground-level cosmic-ray neutrons were measured at various elevations from sea level to 4,000 m in Taiwan, where the vertical cutoff of geomagnetic rigidity is high. High-efficiency Bonner cylinders were used in the measurements. The measured results were used to normalize and confirm one-dimensional transport calculations for cosmic-ray neutrons near interfaces. According to these measurements and calculations, the ground-level neutron fluence rates, effective dose rates, and their altitude dependence in Taiwan were determined. As compared with that reported elsewhere, the appreciable differences both in their absolute values and associated dependence on altitude could be attributed to the substantial latitude effect. In addition, the energy spectra of cosmic-ray neutrons near air/ground and air/water interfaces were measured. The neutron fluence rate near the air/ground interface is greater than that near the air/water interface; however, the spectral shape is harder at the air/water interface than at the air/ground interface. The air/ground and in-flight spectra differ somewhat at low energies, especially in the thermal energy region, but the general shapes of the spectra are similar to each other. The influence of the difference in spectral shape on the evaluation of effective dose rate was investigated.
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Affiliation(s)
- R J Sheu
- Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan, ROC
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43
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Jain R, Prokofiev A, Smirnov A, Tommasino L. Measurement of high energy neutrons by fission reactions. RADIAT MEAS 2001. [DOI: 10.1016/s1350-4487(01)00137-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tume P, Lewis BJ, Bennett LG, Pierre M, Cousins T, Hoffarth BE, Jones TA, Brisson JR. Assessment of the cosmic radiation exposure on Canadian-based routes. HEALTH PHYSICS 2000; 79:568-575. [PMID: 11045532 DOI: 10.1097/00004032-200011000-00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
As a result of the recent recommendations of the ICRP-60 and in anticipation of possible regulation on occupational exposure of commercial aircrew, a two-phase investigation was carried out over a 1-y period to determine the total dose equivalent on representative Canadian-based flight routes. In the first phase of the study, dedicated scientific flights on a Northern round-trip route between Ottawa and Resolute Bay provided the opportunity to characterize the complex mixed-radiation field and to intercompare various instrumentation using both a conventional suite of powered detectors and passive dosimetry. In the second phase, volunteer aircrew carried (passive) neutron bubble detectors during their routine flight duties. From these measurements, the total dose equivalent was derived for a given route with a knowledge of the neutron fraction as determined from the scientific flights and computer code (CARI-3C) calculations. This study has yielded an extensive database of over 3,100 measurements providing the total dose equivalent for 385 different routes. By folding in flight frequency information and the accumulated flight hours, the annual occupational exposures of 20 flight crew have been determined. This study has indicated that most Canadian-based domestic and international aircrew will exceed the proposed annual ICRP-60 public limit of 1 mSv y(-1) but will be well below the occupational limit of 20 mSv y(-1).
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Affiliation(s)
- P Tume
- Royal Military College of Canada, Kingston, Ontario.
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Abstract
The intensity of the different particles making up atmospheric cosmic radiation, their energy distribution, and their potential biological effect on aircraft occupants vary with altitude, geomagnetic latitude, and time in the sun's magnetic activity cycle. Dose rates from cosmic radiation at commercial aviation altitudes are such that crews working on present-day jet aircraft are an occupationally exposed group with a relatively high average effective dose. Crews of future high speed commercial aircraft flying at higher altitudes would be even more exposed. Present calculations of such exposures are uncertain because knowledge of important components of the radiation field comes primarily from theoretical predictions. To help reduce these uncertainties for high-altitude flight, the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) started the Atmospheric Ionizing Radiation (AIR) project. The measurement part of the AIR project is an international collaboration of 12 laboratories placing 14 instruments on multiple flights of a NASA ER-2 aircraft. This paper describes the basic features of cosmic radiation in the atmosphere as they relate to exposure of aircraft occupants and then describes the AIR ER-2 measurements and presents some preliminary results from a series of flights in June 1997.
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Affiliation(s)
- P Goldhagen
- US Department of Energy, Environmental Measurements Laboratory, New York, NY 10014-4811, USA.
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García E, González D, Morales A, Morales J, Ortiz de Solórzano A, Puimedón J, Sáenz C, Salinas A, Sarsa ML, Villar JA. Analysis of airborne radon in an ultra-low background experiment. Appl Radiat Isot 1998; 49:1749-54. [PMID: 9745702 DOI: 10.1016/s0969-8043(98)00061-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The contribution of 222Rn to the background in a low background experiment with a germanium detector has been estimated. We have also checked the efficacy of a standard radon cleaning system. The cleaning reduces the radon concentration two orders of magnitude with respect to the air in the laboratory. The residual 222Rn represents at most 12.5% of the background in the low energy region, a value low enough for the purpose of our experiment. A detailed study of the radioactive background is presented.
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Affiliation(s)
- E García
- Laboratorio de Física Nuclear, Facultad de Ciencias, Universidad de Zaragoza, Spain
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Roesler S, Heinrich W, Schraube H. Neutron spectra in the atmosphere from interactions of primary cosmic rays. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1998; 21:1717-1726. [PMID: 11542891 DOI: 10.1016/s0273-1177(98)00058-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Spectra of neutrons from interactions of primary cosmic rays in the earth's atmosphere are calculated with the Monte Carlo model FLUKA for various depths down to sea level. We discuss the environmental models describing the primary cosmic ray spectrum and details of the calculations. Neutron energy spectra are presented for different depths in the atmosphere and for different geographical locations. By comparing results of calculations to measurements on neutron spectra it is shown that FLUKA may serve as an important tool for the estimation of the radiation environment in the atmosphere.
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Affiliation(s)
- S Roesler
- Universitat Siegen, Fachbereich Physik, Germany
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49
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Tume P, Lewis BJ, Bennett LG, Cousins T. Characterisation of neutron-sensitive bubble detectors for application in the measurement of jet aircrew exposure to natural background radiation. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT 1998; 406:153-168. [PMID: 11542590 DOI: 10.1016/s0168-9002(97)01166-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A survey of the natural background dose equivalent received by Canadian Forces aircrew was conducted using neutron-sensitive bubble detectors (BDs) as the primary detection tool. Since this study was a new application for these detectors, the BD response to neutron dose equivalent (RD) was extended from thermal to 500 MeV in neutron energy. Based upon the extended RD, it was shown that the manufacturer's calibration can be scaled by 1.5 +/- 0.5 to give a BD sensitivity that takes into account recently recommended fluence-to-neutron dose equivalent conversion functions and the cosmogenic neutron spectrum encountered at jet altitudes. An investigation of the effects of systematic bias caused by the cabin environment (i.e., temperature, pressure and relative humidity) on the in-flight measurements was also conducted. Both simulated and actual aircraft climate tests indicated that the detectors are insensitive to the pressure and relative humidity variations encountered during routine jet aircraft operations. Long term conditioning tests also confirmed that the BD-PND model of detector is sensitive to variations in temperature to within +/- 20%. As part of the testing process, the in-flight measurements also demonstrated that the neutron dose equivalent is distributed uniformly throughout a Boeing 707 jet aircraft, indicating that both pilots and flight attendants are exposed to the same neutron field intensity to within experimental uncertainty.
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Affiliation(s)
- P Tume
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston.
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Schraube H, Leuthold G, Roesler S, Heinrich W. Neutron spectra at flight altitudes and their radiological estimation. ADVANCES IN SPACE RESEARCH : THE OFFICIAL JOURNAL OF THE COMMITTEE ON SPACE RESEARCH (COSPAR) 1998; 21:1727-1738. [PMID: 11542892 DOI: 10.1016/s0273-1177(98)00059-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Since the publication of the ICRP-report 60, air crews and other frequently flying persons are considered as occupationally exposed people. At civil flight levels neutrons contribute the major part to the radiologically relevant dose to men. The quantification of the neutron dose, and herewith the radiation risk due to neutrons, suffers from spectral data available especially in the energy range above 20 MeV. Experimental data were recently obtained at a low flight level on top of the mountain Zugspitze at 3000m using a modified Bonner sphere spectrometer. The resulting spectra are compared with Monte-Carlo transport calculations from top of the atmosphere down to 700 g/cm2. These data and others from the literature are used to calculate operational and risk related quantities, i.e. ambient dose equivalent and effective dose.
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Affiliation(s)
- H Schraube
- GSF-Forschungszentrum, Institut fur Strahlenschutz, Neuherberg, Germany
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