| 1. |
- Sihver, Lembit, 1962, et al.
(författare)
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Present status and validation of HIBRAC
- 2009
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Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 44:1, s. 38-46
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes in detail the latest version of HIBRAC, a computer code to calculate one-dimensional deterministic particle transport, designed for application in treatment-planning systems when using highly energetic ions for radiotherapy. HIBRAC can calculate dose, dose-average LET (Linear Energy Transfer), track-average LET, fluence and energy distributions as a function of the penetration depth of light ion beams in any solid and fluid target material. The validity of the code is verified against measured dose and fluence distributions. The code shows good agreement for all the systems studied. (C) 2008 Elsevier Ltd. All rights reserved.
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| 2. |
- Bertucci, Antonella, et al.
(författare)
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Shielding of relativistic protons
- 2007
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 46:2, s. 107-111
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Tidskriftsartikel (refereegranskat)abstract
- Protons are the most abundant element in the galactic cosmic radiation, and the energy spectrum peaks around 1 GeV. Shielding of relativistic protons is therefore a key problem in the radiation protection strategy of crewmembers involved in long-term missions in deep space. Hydrogen ions were accelerated up to 1 GeV at the NASA Space Radiation Laboratory, Brookhaven National Laboratory, New York. The proton beam was also shielded with thick ( about 20 g/cm(2)) blocks of lucite (PMMA) or aluminium ( Al). We found that the dose rate was increased 40-60% by the shielding and decreased as a function of the distance along the axis. Simulations using the General Purpose Particle and Heavy-Ion Transport code System (PHITS) show that the dose increase is mostly caused by secondary protons emitted by the target. The modified radiation Weld after the shield has been characterized for its biological eVectiveness by measuring chromosomal aberrations in human peripheral blood lymphocytes exposed just behind the shield block, or to the direct beam, in the dose range 0.53 Gy. Notwithstanding the increased dose per incident proton, the fraction of aberrant cells at the same dose in the sample position was not significantly modified by the shield. The PHITS code simulations show that, albeit secondary protons are slower than incident nuclei, the LET spectrum is still contained in the low-LET range (
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| 3. |
- Hayatsu, K., et al.
(författare)
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Lunar radiation dose due to cosmic rays and their secondary particles
- 2010
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Ingår i: 61st International Astronautical Congress 2010, IAC 2010.Prague, 27 September-1 October 2010. - 9781617823688 ; 5, s. 4084-4088
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Konferensbidrag (refereegranskat)abstract
- To be able to safely perform human activities on the lunar surface, it is very important to assess the radiation environment, including the dose from galactic cosmic Rays (GCRs) and large Solar Energetic Particles (SEPs). Especially, large SPEs are highly hazardous to lunar habitants. In this paper, several SPEs have been evaluated in order to estimate the effective dose equivalent on the lunar surface. Several events give more than 1 Sv without any shield.
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| 4. |
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| 5. |
- La Tessa, Chiara, 1979, et al.
(författare)
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Fragmentation of 1 GeV/nucleon iron ions in thick targets relevant for space exploration
- 2005
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Ingår i: Advances in Space Research. - : Elsevier BV. - 1879-1948 .- 0273-1177. ; 35:2, s. 223-229
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Tidskriftsartikel (refereegranskat)abstract
- We have measured charged nuclear fragments produced by 1 GeV/nucleon 56 Fe ions interacting with aluminium, polyethylene and lead. These materials are relevant for assessment of radiation risk for manned space flight. The data will be presented in a form suitable for comparison with models of nuclear fragmentation and transport, including linear energy transfer (LET) spectrum, fluence for iron and fragments, event-tack- and even t-dose-averaged LET, total dose and iron contribution to dose.
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| 6. |
- La Tessa, Chiara, 1979, et al.
(författare)
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Test of weak and strong factorization in nucleus-nucleus collisions at several hundred MeV/nucleon
- 2007
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 791:3-4, s. 434-450
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Tidskriftsartikel (refereegranskat)abstract
- Projectile total and partial charge-changing cross sections have been measured for argon ions at 400 MeV/nucleon in carbon, aluminum, copper, tin and lead targets; cross sections for hydrogen were also obtained using a polyethylene target. The validity of weak and strong factorization properties has been investigated for partial charge-changing cross sections; measurements obtained for carbon, neon and silicon beams at 290 and 400 MeV/nucleon and iron beam at 400 MeV/nucleon, in carbon, aluminum, copper, tin and lead targets have also been used for the test. Two different analysis methods were applied and both indicated that these properties are valid, without any significant difference between weak and strong factorization. The factorization parameters have then been calculated and analyzed in order to find some systematic behavior useful for modeling purposes. (C) 2007 Elsevier B.V. All rights reserved.
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| 7. |
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| 8. |
- Niita, K., et al.
(författare)
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Event Generator Models in the Particle and Heavy Ion Transport Code System; PHITS
- 2011
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Ingår i: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884. ; 59:2, s. 827-832
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Tidskriftsartikel (refereegranskat)abstract
- We present the event generator rnodels incorporated in the particle and heavy ion transport code system PHITS. For the high energy nuclear reactions, we discuss the QMD model and the INC model followed by the statistical decay model. For low energy neutron transport by using the nuclear data, we propose a new model, in which we combine the evaluated nuclear data and the reaction models so as to describe all ejectiles of collision keeping the energy and momentum conservation. By this new model, we can estimate new quantities which are related to the higher order correlations beyond one-body observable, for an example, the deposit energy distribution in a cell, which cannot be obtained by the transport calculation based on the Boltzmann equation with the evaluated nuclear data.
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| 9. |
- Pachnerova Brabcová, Katerina, 1978, et al.
(författare)
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Clustered DNA damage on subcellular level: effect of scavengers
- 2014
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 53:4, s. 705-712
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Tidskriftsartikel (refereegranskat)abstract
- Clustered DNA damages are induced by ionizing radiation, particularly of high linear energy transfer (LET). Compared to isolated DNA damage sites, their biological effects can be more severe. We investigated a clustered DNA damage induced by high LET radiation (C 290 MeV u(-1) and Fe 500 MeV u(-1)) in pBR322 plasmid DNA. The plasmid is dissolved in pure water or in aqueous solution of one of the three scavengers (coumarin-3-carboxylic acid, dimethylsulfoxide, and glycylglycine). The yield of double strand breaks (DSB) induced in the DNA plasmid-scavenger system by heavy ion radiation was found to decrease with increasing scavenging capacity due to reaction with hydroxyl radical, linearly with high correlation coefficients. The yield of non-DSB clusters was found to occur twice as much as the DSB. Their decrease with increasing scavenging capacity had lower linear correlation coefficients. This indicates that the yield of non-DSB clusters depends on more factors, which are likely connected to the chemical properties of individual scavengers.
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| 10. |
- Pachnerova Brabcová, Katerina, 1978, et al.
(författare)
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Dose Distribution Outside the Target Volume for 170-Mev Proton Beam
- 2014
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 161:1-4, s. 410-416
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Tidskriftsartikel (refereegranskat)abstract
- Dose delivered outside the proton field during radiotherapy can potentially lead to secondary cancer development. Measurements with a 170-MeV proton beam were performed with passive detectors (track etched detectors and thermoluminescence dose-meters) in three different depths along the Bragg curve. The measurement showed an uneven decrease of the dose outside of the beam field with local enhancements. The major contribution to the delivered dose is due to high-energy protons with linear energy transfer (LET) up to 10 keV mu m(-1). However, both measurement and preliminary Monte Carlo calculation also confirmed the presence of particles with higher LET.
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