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Mares V, Farah J, De Saint-Hubert M, Domański S, Domingo C, Dommert M, Kłodowska M, Krzempek K, Kuć M, Martínez-Rovira I, Michaś E, Mojżeszek N, Murawski Ł, Ploc O, Romero-Expósito M, Tisi M, Trompier F, Van Hoey O, Van Ryckeghem L, Wielunski M, Harrison RM, Stolarczyk L, Olko P. Neutron Radiation Dose Measurements in a Scanning Proton Therapy Room: Can Parents Remain Near Their Children During Treatment? Front Oncol 2022; 12:903706. [PMID: 35912238 PMCID: PMC9330633 DOI: 10.3389/fonc.2022.903706] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/16/2022] [Indexed: 11/15/2022] Open
Abstract
Purpose This study aims to characterize the neutron radiation field inside a scanning proton therapy treatment room including the impact of different pediatric patient sizes. Materials and Methods Working Group 9 of the European Radiation Dosimetry Group (EURADOS) has performed a comprehensive measurement campaign to measure neutron ambient dose equivalent, H*(10), at eight different positions around 1-, 5-, and 10-year-old pediatric anthropomorphic phantoms irradiated with a simulated brain tumor treatment. Several active detector systems were used. Results The neutron dose mapping within the gantry room showed that H*(10) values significantly decreased with distance and angular deviation with respect to the beam axis. A maximum value of about 19.5 µSv/Gy was measured along the beam axis at 1 m from the isocenter for a 10-year-old pediatric phantom at 270° gantry angle. A minimum value of 0.1 µSv/Gy was measured at a distance of 2.25 m perpendicular to the beam axis for a 1-year-old pediatric phantom at 140° gantry angle. The H*(10) dependence on the size of the pediatric patient was observed. At 270° gantry position, the measured neutron H*(10) values for the 10-year-old pediatric phantom were up to 20% higher than those measured for the 5-year-old and up to 410% higher than for the 1-year-old phantom, respectively. Conclusions Using active neutron detectors, secondary neutron mapping was performed to characterize the neutron field generated during proton therapy of pediatric patients. It is shown that the neutron ambient dose equivalent H*(10) significantly decreases with distance and angle with respect to the beam axis. It is reported that the total neutron exposure of a person staying at a position perpendicular to the beam axis at a distance greater than 2 m from the isocenter remains well below the dose limit of 1 mSv per year for the general public (recommended by the International Commission on Radiological Protection) during the entire treatment course with a target dose of up to 60 Gy. This comprehensive analysis is key for general neutron shielding issues, for example, the safe operation of anesthetic equipment. However, it also enables the evaluation of whether it is safe for parents to remain near their children during treatment to bring them comfort. Currently, radiation protection protocols prohibit the occupancy of the treatment room during beam delivery.
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Affiliation(s)
- Vladimir Mares
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
- *Correspondence: Vladimir Mares,
| | - Jad Farah
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, Fontenay-aux-Roses, France
| | - Marijke De Saint-Hubert
- Belgian Nuclear Research Center, (SCK CEN), Institute for Environment, Health and Safety (EHS), Mol, Belgium
| | - Szymon Domański
- National Centre for Nuclear Research, Radiological Metrology and Biomedical Physics Division, Otwock-Świerk, Poland
| | - Carles Domingo
- Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Martin Dommert
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
| | - Magdalena Kłodowska
- Cambridge University Hospital National Health Service (NHS) Trust, Medical Physics, Cambridge, United Kingdom
| | - Katarzyna Krzempek
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
| | - Michał Kuć
- National Centre for Nuclear Research, Radiological Metrology and Biomedical Physics Division, Otwock-Świerk, Poland
| | | | - Edyta Michaś
- National Centre for Nuclear Research, Radiological Metrology and Biomedical Physics Division, Otwock-Świerk, Poland
| | - Natalia Mojżeszek
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
| | - Łukasz Murawski
- National Centre for Nuclear Research, Radiological Metrology and Biomedical Physics Division, Otwock-Świerk, Poland
| | - Ondrej Ploc
- Department of Radiation Dosimetry, Nuclear Physics Institute of the Czech Academy of Sciences (CAS), Prague, Czechia
| | | | - Marco Tisi
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
| | - François Trompier
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, Fontenay-aux-Roses, France
| | - Olivier Van Hoey
- Belgian Nuclear Research Center, (SCK CEN), Institute for Environment, Health and Safety (EHS), Mol, Belgium
| | - Laurent Van Ryckeghem
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-Santé, Fontenay-aux-Roses, France
| | - Marek Wielunski
- Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
| | - Roger M. Harrison
- Faculty of Medical Sciences, University of Newcastle upon Tyne, Newcastle upon Tyne, United Kingdom
| | - Liliana Stolarczyk
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
- Danish Centre for Particle Therapy, Aarhus University Hospital (AUH), Aarhus, Denmark
| | - Pawel Olko
- Institute of Nuclear Physics, Polish Academy of Sciences, (IFJ PAN), Krakow, Poland
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Englbrecht FS, Trinkl S, Mares V, Rühm W, Wielunski M, Wilkens JJ, Hillbrand M, Parodi K. A comprehensive Monte Carlo study of out-of-field secondary neutron spectra in a scanned-beam proton therapy gantry room. Z Med Phys 2021; 31:215-228. [PMID: 33622567 DOI: 10.1016/j.zemedi.2021.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/18/2020] [Accepted: 01/05/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To simulate secondary neutron radiation fields that had been measured at different relative positions during phantom irradiation inside a scanning proton therapy gantry treatment room. Further, to identify origin, energy distribution, and angular emission of the secondary neutrons as a function of proton beam energy. METHODS The FLUKA Monte Carlo code was used to model the relevant parts of the treatment room in a scanned pencil beam proton therapy gantry including shielding walls, floor, major metallic gantry-components, patient table, and a homogeneous PMMA target. The proton beams were modeled based on experimental beam ranges in water and spot shapes in air. Neutron energy spectra were simulated at 0°, 45°, 90° and 135° relative to the beam axis at 2m distance from isocenter for monoenergetic 11×11cm2 fields from 200MeV, 140MeV, 75MeV initial proton beams, as well as for 118MeV protons with a 5cm thick PMMA range shifter. The total neutron spectra were scored for these four positions and proton energies. FLUKA neutron spectra simulations were crosschecked with Geant4 simulations using initial proton beam properties from FLUKA-generated phase spaces. Additionally, the room-components generating secondary neutrons in the room and their contributions to the total spectrum were identified and quantified. RESULTS FLUKA and Geant4 simulated neutron spectra showed good general agreement with published measurements in the whole simulated neutron energy range of 10-10 to 103MeV. As in previous studies, high-energy (E≥19.6MeV) neutrons from the phantom are most prevalent along 0°, while thermalized (1meV≤E<0.4eV) and fast (100keV≤E<19.4MeV) neutrons dominate the spectra in the lateral and backscatter direction. The iron of the large bending magnet and its counterweight mounted on the gantry were identified as the most determinant sources of secondary fast-neutrons, which have been lacking in simplified room simulations. CONCLUSIONS The results helped disentangle the origin of secondary neutrons and their dominant contributions and were strengthened by the fact that a cross comparison was made using two independent Monte Carlo codes. The complexity of such room model can in future be limited using the result. They may further be generalized in that they can be used for an assessment of neutron fields, possibly even at facilities where detailed neutron measurements and simulations cannot be performed. They may also help to design future proton therapy facilities and to reduce unwanted radiation doses from secondary neutrons to patients.
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Affiliation(s)
- Franz S Englbrecht
- LMU Munich, Faculty of Physics, Department of Medical Physics, Am Coulombwall 1, 85748 Garching bei München, Germany.
| | - Sebastian Trinkl
- Helmholtz Zentrum München, Institute of Radiation Medicine, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany; Technical University of Munich, Physics Department, James-Franck-Straße 1, 85748 Garching bei München, Germany
| | - Vladimír Mares
- Helmholtz Zentrum München, Institute of Radiation Medicine, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Werner Rühm
- Helmholtz Zentrum München, Institute of Radiation Medicine, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Marek Wielunski
- Helmholtz Zentrum München, Institute of Radiation Medicine, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
| | - Jan J Wilkens
- Technical University of Munich, Physics Department, James-Franck-Straße 1, 85748 Garching bei München, Germany; Technical University of Munich, Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Ismaninger Str. 22, 81675 München, Germany
| | - Martin Hillbrand
- Rinecker Proton Therapy Center, Schäftlarnstraße 133, 81371 München, Germany
| | - Katia Parodi
- LMU Munich, Faculty of Physics, Department of Medical Physics, Am Coulombwall 1, 85748 Garching bei München, Germany
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Ambrožová I, Beck P, Benton ER, Billnert R, Bottollier-Depois JF, Caresana M, Dinar N, Domański S, Gryziński MA, Kákona M, Kolros A, Krist P, Kuć M, Kyselová D, Latocha M, Leuschner A, Lillhök J, Maciak M, Mareš V, Murawski Ł, Pozzi F, Reitz G, Schennetten K, Silari M, Šlegl J, Sommer M, Štěpán V, Trompier F, Tscherne C, Uchihori Y, Vargas A, Viererbl L, Wielunski M, Wising M, Zorloni G, Ploc O. REFLECT – Research flight of EURADOS and CRREAT: Intercomparison of various radiation dosimeters onboard aircraft. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106433] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Brall T, Dommert M, Rühm W, Trinkl S, Wielunski M, Mares V. Monte Carlo simulation of the CERN-EU High Energy Reference Field (CERF) facility. RADIAT MEAS 2020. [DOI: 10.1016/j.radmeas.2020.106294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Trinkl S, Mares V, Englbrecht FS, Wilkens JJ, Wielunski M, Parodi K, Rühm W, Hillbrand M. Systematic out-of-field secondary neutron spectrometry and dosimetry in pencil beam scanning proton therapy. Med Phys 2017; 44:1912-1920. [DOI: 10.1002/mp.12206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/17/2016] [Accepted: 12/18/2016] [Indexed: 12/20/2022] Open
Affiliation(s)
- Sebastian Trinkl
- Institute of Radiation Protection; Helmholtz Zentrum München (HMGU); Neuherberg Germany
- Department of Physik; Technical University of Munich; Munich Germany
| | - Vladimir Mares
- Institute of Radiation Protection; Helmholtz Zentrum München (HMGU); Neuherberg Germany
| | | | - Jan Jakob Wilkens
- Department of Physik; Technical University of Munich; Munich Germany
- Department of Radiation Oncology; Technical University of Munich, Klinikum rechts der Isar; Munich Germany
| | - Marek Wielunski
- Institute of Radiation Protection; Helmholtz Zentrum München (HMGU); Neuherberg Germany
| | - Katia Parodi
- Department of Medical Physics; Ludwig-Maximilians-Universität München; Garching b. München Germany
| | - Werner Rühm
- Institute of Radiation Protection; Helmholtz Zentrum München (HMGU); Neuherberg Germany
| | - Martin Hillbrand
- Department of Medical Physics; Rinecker Proton Therapy Center; Munich Germany
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Englbrecht F, Trinkl S, Mares V, Ruehm W, Wielunski M, Wilkens J, Hillbrand M, Parodi K. SU-F-T-217: A Comprehensive Monte-Carlo Study of Out-Of-Field Secondary Neutron Spectra in a Scanned-Beam Proton Therapy Treatment Room. Med Phys 2016. [DOI: 10.1118/1.4956356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Mares V, Romero-Expósito M, Farah J, Trinkl S, Domingo C, Dommert M, Stolarczyk L, Van Ryckeghem L, Wielunski M, Olko P, Harrison RM. A comprehensive spectrometry study of a stray neutron radiation field in scanning proton therapy. Phys Med Biol 2016; 61:4127-40. [PMID: 27171358 DOI: 10.1088/0031-9155/61/11/4127] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The purpose of this study is to characterize the stray neutron radiation field in scanning proton therapy considering a pediatric anthropomorphic phantom and a clinically-relevant beam condition. Using two extended-range Bonner sphere spectrometry systems (ERBSS), Working Group 9 of the European Radiation Dosimetry Group measured neutron spectra at ten different positions around a pediatric anthropomorphic phantom irradiated for a brain tumor with a scanning proton beam. This study compares the different systems and unfolding codes as well as neutron spectra measured in similar conditions around a water tank phantom. The ten spectra measured with two ERBSS systems show a generally similar thermal component regardless of the position around the phantom while high energy neutrons (above 20 MeV) were only registered at positions near the beam axis (at 0°, 329° and 355°). Neutron spectra, fluence and ambient dose equivalent, H (*)(10), values of both systems were in good agreement (<15%) while the unfolding code proved to have a limited effect. The highest H (*)(10) value of 2.7 μSv Gy(-1) was measured at 329° to the beam axis and 1.63 m from the isocenter where high-energy neutrons (E ⩾ 20 MeV) contribute with about 53%. The neutron mapping within the gantry room showed that H (*)(10) values significantly decreased with distance and angular position with respect to the beam axis dropping to 0.52 μSv Gy(-1) at 90° and 3.35 m. Spectra at angles of 45° and 135° with respect to the beam axis measured here with an anthropomorphic phantom showed a similar peak structure at the thermal, fast and high energy range as in the previous water-tank experiments. Meanwhile, at 90°, small differences at the high-energy range were observed. Using ERBSS systems, neutron spectra mapping was performed to characterize the exposure of scanning proton therapy patients. The ten measured spectra provide precise information about the exposure of healthy organs to thermal, epithermal, evaporation and intra-nuclear cascade neutrons. This comprehensive spectrometry analysis can also help in understanding the tremendous literature data based rem-counters while also being of great value for general neutron shielding and radiation safety studies.
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Affiliation(s)
- Vladimir Mares
- Helmholtz Zentrum München, Institute of Radiation Protection, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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Farah J, Mares V, Romero-Expósito M, Trinkl S, Domingo C, Dufek V, Klodowska M, Kubancak J, Knežević Ž, Liszka M, Majer M, Miljanić S, Ploc O, Schinner K, Stolarczyk L, Trompier F, Wielunski M, Olko P, Harrison RM. Measurement of stray radiation within a scanning proton therapy facility: EURADOS WG9 intercomparison exercise of active dosimetry systems. Med Phys 2015; 42:2572-84. [DOI: 10.1118/1.4916667] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Abstract
Here the latest development stages of the HMGU active neutron dosemeter are presented. This work includes the comparison of the dosemeter's response function, calculated with Geant4, and the measurements in monoenergetic neutron fields at the Physikalisch Technische Bundesanstalt in Braunschweig, Germany. These results were used to match the response function and the count-to-dose conversion factors of the dosemeter to the Hp(10) personal dose equivalent.
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Affiliation(s)
- F Bergmeier
- Helmholtz Center Munich, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - M Volnhals
- In-SITU GmbH (former Helmholtz Center Munich), 82054 Sauerlach, Germany
| | - M Wielunski
- Helmholtz Center Munich, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
| | - W Rühm
- Helmholtz Center Munich, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany
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Farah J, Stolarczyk L, Algranati C, Domingo C, Dufek V, Fellin F, Frojdh E, George S, Harrison R, Klodowska M, Kubancak J, Knezevic Z, Liszka M, Majer M, Mares V, Miljanic S, Ploc O, Romero-Exposito M, Ruhm W, Schinner K, Schwarz M, Trinkl S, Trompier F, Wielunski M, Olko P. WE-D-17A-05: Measurement of Stray Radiation Within An Active Scanning Proton Therapy Facility: EURADOS WG9 Intercomparison Exercise of Active Dosimetry Systems. Med Phys 2014. [DOI: 10.1118/1.4889408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Gierl S, Meisenberg O, Haninger T, Wielunski M, Tschiersch J. An unattended device for high-voltage sampling and passive measurement of thoron decay products. Rev Sci Instrum 2014; 85:022103. [PMID: 24593339 DOI: 10.1063/1.4865163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An integrating measurement device for the concentration of airborne thoron decay products was designed and calibrated. It is suitable for unattended use over up to several months also in inhabited dwellings. The device consists of a hemispheric capacitor with a wire mesh as the outer electrode on ground potential and the sampling substrates as the inner electrode on +7.0 kV. Negatively charged and neutral thoron decay products are accelerated to and deposited on the sampling substrates. As sampling substrates, CR39 solid-state nuclear track detectors are used in order to record the alpha decay of the sampled decay products. Nuclide discrimination is achieved by covering the detectors with aluminum foil of different thickness, which are penetrated only by alpha particles with sufficient energy. Devices of this type were calibrated against working level monitors in a thoron experimental house. The sensitivity was measured as 9.2 tracks per Bq/m(3) × d of thoron decay products. The devices were used over 8 weeks in several houses built of earthen material in southern Germany, where equilibrium equivalent concentrations of 1.4-9.9 Bq/m(3) of thoron decay products were measured.
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Affiliation(s)
- Stefanie Gierl
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Oliver Meisenberg
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Thomas Haninger
- Helmholtz Zentrum München, German Research Center for Environmental Health, Auswertungsstelle für Strahlendosimeter, Otto-Hahn-Ring 6, 81739 München, Germany
| | - Marek Wielunski
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Jochen Tschiersch
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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Abstract
For state-of-the-art discrimination of Radon and Thoron several measurement techniques can be used, such as active sampling, electrostatic collection, delayed coincidence method, and alpha-particle-spectroscopy. However, most of the devices available are bulky and show high power consumption, rendering them unfeasible for personal exposition monitoring. Based on a Radon exposure meter previously realized at the Helmholtz Center Munich (HMGU), a new electronic prototype for Radon/Thoron monitoring is currently being developed, which features small size and weight. Operating with pin-diode detectors, the low-power passive-sampling device can be used for continuous concentration measurements, employing alpha-particle-spectroscopy and coincidence event registration to distinguish decays originating either from Radon or Thoron isotopes and their decay products. In open geometry, preliminary calibration measurements suggest that one count per hour is produced by a 11 Bq m(-3) Radon atmosphere or by a 15 Bq m(-3) Thoron atmosphere. Future efforts will concentrate on measurements in mixed Radon/Thoron atmospheres.
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Affiliation(s)
- J Irlinger
- ISS, Helmholtz Center Munich, Research Center for Environment and Health, 85764 Neuherberg, Germany
| | - M Wielunski
- ISS, Helmholtz Center Munich, Research Center for Environment and Health, 85764 Neuherberg, Germany
| | - W Rühm
- ISS, Helmholtz Center Munich, Research Center for Environment and Health, 85764 Neuherberg, Germany
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Stolarczyk L, Knežević Ž, Adamek N, Algranati C, Ambrozova I, Domingo C, Dufek V, Farah J, Fellin F, Klodowska M, Kubancak J, Liszka M, Majer M, Mares V, Miljanić S, Ploc O, Romero-Expósito M, Schinner K, Schwarz M, Trinkl S, Trompier F, Wielunski M, Harrison R, Olko P. Comparison of passive dosimeters for secondary radiation measurements in scanning proton radiotherapy. Phys Med 2014. [DOI: 10.1016/j.ejmp.2014.07.197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Bi L, Tschiersch J, Meisenberg O, Wielunski M, Li JL, Shang B. Development of a new thoron progeny detector based on SSNTD and the collection by an electric field. Radiat Prot Dosimetry 2011; 145:288-294. [PMID: 21493610 DOI: 10.1093/rpd/ncr078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The importance of (220)Rn (thoron) progeny for human exposure has been widely recognised in the past decades. Since no stable equilibrium factor was found between indoor thoron and its progeny, and the concentration of thoron progeny varies with time, it is necessary to develop detectors for long-term measurement that directly sample and detect thoron progeny. However, power supply of this kind of detectors has always been a problem. In this study, a set of device that is suitable for long-term measurement is introduced. A high-voltage electric field was formed for the collection of charged aerosols attached by (222)Rn (radon) and thoron progenies on solid-state nuclear track detector. Impact from radon progeny could be eliminated with a shield of Al foil of appropriate thickness. Tests were made both in an experimental house and in a thoron chamber in Helmholtz Zentrum München to determine the parameters and to verify the universality under different conditions.
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Affiliation(s)
- L Bi
- Helmholtz Zentrum München - German Research Centre for Environmental Health, Institute of Radiation Protection, 85764 Neuherberg, Germany
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Schütz R, Fehrenbacher G, Wielunski M, Wahl W. A three si detector system for personnel neutron dosimetry developed by means of Monte Carlo simulation calculations. Radiat Prot Dosimetry 2003; 104:17-26. [PMID: 12862239 DOI: 10.1093/oxfordjournals.rpd.a006157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The aim of this study was the development of an electronic detection system for personnel neutron dosimetry. Converter type silicon detectors were used for neutron detection. Measurements to obtain pulse height distributions were performed in neutron fields in the energy range from thermal to 14.8 MeV. They were compared with pulse height distributions calculated by means of Monte Carlo simulation programs, and their shapes and total count responses agreed very well. Based on these calculations a three-detector system for the measurement of the individual dose equivalent, Hp(10), was developed. Response functions of the system were calculated, and their dependence on angles from 0 degrees to 75 degrees was investigated. The detector system was exposed in several neutron fields and the agreement of the determined dose values with the reference dose values (0.1 mSv to 6 mSv) was better than a factor of 2, even for quasi-monoenergetic neutrons, and for angles in the range of 0 degrees, 30 degrees and 60 degrees. The detector system should be able to measure a dose range down to 10 microSv depending on the neutron energy.
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Affiliation(s)
- R Schütz
- Gesellschaft für Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany.
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Bubert H, Grallath E, Quentmeier A, Wielunski M, Borucki L. Comparative investigation on copper oxides by depth profiling using XPS, RBS and GDOES. Anal Bioanal Chem 1995; 353:456-63. [PMID: 15048518 DOI: 10.1007/s0021653530456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/1995] [Accepted: 03/08/1995] [Indexed: 10/26/2022]
Abstract
Depth profiling has been performed by using X-ray photoelectron spectrometry (XPS) in combination with Ar-ion sputtering, Rutherford backscattering spectrometry (RBS) and glow discharge optical emission spectrometry (GDOES). The data obtained by XPS have been subjected to factor analysis in order to determine the compositional layering of the copper oxides. This leads to two or three relevant components within the oxide layers consisting of Cu(2)O or CuO dependent on the sample preparation. GDOES measurements show sputtering profiles which are seriously influenced by a varying sputter rate. To ensure the results obtained so far, RBS measurements of the oxide layers have been carried out in order to discover artefacts of the other methods used and to demonstrate the excellent suitability of RBS for quantitative analysis of these layers. Chemical analysis consisting of (1) carrier-gas fusion analysis (CGFA) and (2) selective dissolution of Cu(2)O/CuO allows the determination of the total amount of oxygen and copper, respectively, and can serve as a cornerstone of quantitative analysis.
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Affiliation(s)
- H Bubert
- Institut für Spektrochemie und angewandte Spektroskopie (ISAS), Bunsen-Kirchhoff-Strasse 11, D-44139, Dortmund, Germany
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Bubert H, Korte M, Garten RP, Grallath E, Wielunski M. Application of factor analysis in electron spectroscopic depth profiling on copper oxide. Anal Chim Acta 1994. [DOI: 10.1016/0003-2670(94)00053-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Bubert H, Burba P, Klockenk�mper R, Sch�nborn A, Wielunski M. Dose determination of nickel implantations in silicon wafers. Anal Bioanal Chem 1991. [DOI: 10.1007/bf00321556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wielunski M, Auleytner J, Czarnecki S, Turos A, Wielunska D. Influence of non-uniformity of laser beam intensity on the surface layer structure of implanted silicon crystals. Cryst Res Technol 1982. [DOI: 10.1002/crat.2170170211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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