| 1. |
- Adolfsson, Emelie, et al.
(författare)
-
Optimisation of an EPR dosimetry system for robust and high precision dosimetry
- 2014
-
Ingår i: Radiation Measurements. - : Elsevier. - 1350-4487 .- 1879-0925. ; 70, s. 21-28
-
Tidskriftsartikel (refereegranskat)abstract
- Clinical applications of electron paramagnetic resonance (EPR) dosimetry systems demand high accuracy causing time consuming analysis. The need for high spatial resolution dose measurements in regions with steep dose gradients demands small sized dosimeters. An optimization of the analysis was therefore needed to limit the time consumption. The aim of this work was to introduce a new smaller lithium formate dosimeter model (diameter reduced from standard diameter 4.5 mm to 3 mm and height from 4.8 mm to 3 mm). To compensate for reduced homogeneity in a batch of the smaller dosimeters, a method for individual sensitivity correction suitable for EPR dosimetry was tested. Sensitivity and repeatability was also tested for a standard EPR resonator and a super high Q (SHQE) one. The aim was also to optimize the performance of the dosimetry system for better efficiency regarding measurement time and precision. A systematic investigation of the relationship between measurement uncertainty and number of readouts per dosimeter was performed. The conclusions drawn from this work were that it is possible to decrease the dosimeter size with maintained measurement precision by using the SHQE resonator and introducing individual calibration factors for dosimeter batches. It was also shown that it is possible reduce the number of readouts per dosimeter without significantly decreasing the accuracy in measurements.
|
|
| 2. |
- Ambrozova, I., et al.
(författare)
-
Measurement of target fragments produced by 160 MeV proton beam in aluminum and polyethylene with CR-39 plastic nuclear track detectors
- 2014
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 64, s. 29-34
-
Tidskriftsartikel (refereegranskat)abstract
- Production of target fragments from reactions of 160 MeV proton beams in aluminum and polyethylene was measured with CR-39 plastic nuclear track detectors (PNTD). Due to the detection limit of PNTD, primary protons cannot be detected; only low-energy short-range target fragments are registered. As a feasibility study, a so called "two step etching method" was employed to get the linear energy transfer (LET) spectra, absorbed dose, and dose equivalent. This method is discussed in this paper, together with the measured results. (C) 2014 Elsevier Ltd. All rights reserved.
|
|
| 3. |
- Andersson, P., et al.
(författare)
-
An upgrade of the SCANDAL setup for measurements of elastic neutron scattering at 175 MeV
- 2010
-
Ingår i: RADIATION MEASUREMENTS. - : Elsevier BV. ; 45:10, s. 1142-1144
-
Konferensbidrag (refereegranskat)abstract
- The experimental setup SCANDAL used for measurements of the differential cross section for elastic and inelastic neutron scattering, has recently been upgraded with larger CsI scintillating detectors to enable measurements at energies up to 175 MeV. Measurements on Fe. Bi and Si have been carried out using the quasi mono-energetic neutron beam at the The Svedberg Laboratory, and data is under analysis. The experimental setup can be used for measurements on a wide range of target nuclei, including C and O, which are important for dosimetry applications. SCANDAL can also run in proton mode, for measurements of the (n,p) reaction. This paper describes the new experimental setup, and reports on its properties, such as energy resolution.
|
|
| 4. |
- Bassinet, C., et al.
(författare)
-
Retrospective radiation dosimetry using OSL of electronic components: Results of an inter-laboratory comparison
- 2014
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1879-0925 .- 1350-4487. ; 71, s. 475-479
-
Tidskriftsartikel (refereegranskat)abstract
- In the framework of the EU-FP7 MULTIBIODOSE project, two protocols using OSL of resistors removed from the circuit board of mobile phones were developed with the aim to use the resistors as fortuitous dosimeters in the event of a large scale radiological accident. This paper presents the results of an inter-laboratory comparison carried out under the umbrella of EURADOS. The two aims of this exercise were the validation of the MULTIBIODOSE protocols by a large number of laboratories and the dissemination of the method with the objective of preparing the basis for a network that could increase Europe's response capacity in the case of a mass casualty radiological emergency. Twelve institutes from eleven European countries and one institute from the USA, with various degrees of expertise in OSL dosimetry, took part in the OSL inter-laboratory comparison. Generally, a good agreement within uncertainties was observed between estimated and nominal doses. (C) 2014 Elsevier Ltd. All rights reserved.
|
|
| 5. |
- Bevilacqua, Riccardo, et al.
(författare)
-
Neutron induced light-ion production from iron and bismuth at 175 MeV
- 2010
-
Ingår i: RADIATION MEASUREMENTS. - : Elsevier BV. ; 45:10, s. 1145-1150
-
Konferensbidrag (refereegranskat)abstract
- We have measured light-ion (p, d, t, He-3 and alpha) production in the interaction of 175 MeV neutrons with iron and bismuth with low-energy thresholds and for a wide angular range (from 20 degrees to 160 degrees, in steps of 20 degrees). Measurements have been performed with the Medley setup, semi-permanently installed at the The Svedberg Laboratory, Uppsala (Sweden), where a quasi-monoenergetic neutron beam is available and well characterized. Medley is a conventional spectrometer system and consists of eight telescopes, each of them composed of two silicon surface barrier detectors, to perform particle identification, and a CsI(Tl) scintillator to fully measure the kinetic energy of the produced light-ions. We report preliminary double-differential cross sections for production of protons, deuterons and tritons in comparison with model calculations using TALYS-1.0 code. These show better agreement for the production of protons, while the theoretical calculations seem to overestimate the experimental production of deuterons and tritons.
|
|
| 6. |
- Broggio, D., et al.
(författare)
-
Child and adult thyroid monitoring after a reactor accident (CAThyMARA): Technical recommendations and remaining gaps
- 2019
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 128:Septemberg
-
Tidskriftsartikel (refereegranskat)abstract
- © 2019 Elsevier Ltd Following a severe nuclear reactor accident large amounts of radioactive iodine are released in the atmosphere. Health consequences estimation for the affected population is based on the dose assessment which can be derived from in vivo measurements. Since the uptake of radioactive iodine increases the thyroid cancer risk of children it is of particular interest to dispose of technical recommendations on thyroid monitoring, particularly for children. This paper summarizes recommendations that have been issued by a group of European radiation protection specialists during the CAThyMARA project. It covers technical aspects such as the choice of instruments, the calibration process, the measurement preparedness, the dose assessment and communication issues. This paper also discusses remaining gaps and serves as an introduction to other papers of this special issue.
|
|
| 7. |
- Christiansson, Maria, et al.
(författare)
-
OSL in NaCl vs. TL in LiF for absorbed dose measurements and radiation quality assessment in the photon energy range 20 keV to 1.3 MeV
- 2018
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487. ; 112, s. 11-15
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to determine the photon energy dependence of absorbed dose measurements, in a comparison of optically stimulated luminescence (OSL) in NaCl with thermoluminescence (TL) in LiF:Mg,Cu,P. The comparisons were made at exposure to ionizing radiation in the photon energy range 20 keV to 1.3 MeV. Specially designed dosemeter kits containing both NaCl and LiF were used under i) laboratory conditions using defined radiation fields, ii) laboratory conditions using sealed point sources mimicking unintentional exposures, and iii) field conditions in areas in Japan that were affected by the Fukushima Daiichi nuclear disaster in 2011. The dosemeter kits used in Japan showed that absorbed doses as low as 100 μGy can be assessed from the OSL signal in NaCl. The ratio of the dosemeter readings using OSL in NaCl and TL in LiF increases after irradiation at lower photon energies (less than a few hundred keV) as determined under laboratory conditions. Compensating for this energy dependence of the absorbed dose determinations obtained from OSL in NaCl would thus require an energy-dependent conversion factor for photon energies below 600 keV. On the other hand, the difference in the photon energy dependence between NaCl and LiF may be used to assess the mean effective energy of the photon field. The signal ratios between NaCl and LiF after exposure to radiation in the Fukushima Dashii contaminated areas in Japan, 1.67 ± 0.26 (2013) and 1.63 ± 0.32 (2015), indicate that the mean photon energy in this area was 300–400 keV during the years of the survey.
|
|
| 8. |
- Daya, DDNB, et al.
(författare)
-
Interaction of mev atomic ions with molecular solids: Ion track structure and sputtering phenomena
- 1997
-
Ingår i: RADIATION MEASUREMENTS. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1350-4487. ; 28:1-6, s. 101-110
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Recent results obtained in our research groups from studies of the interactions of swift, heavy atomic ions with molecular solids are concisely outlined. The focus is on material ejection (sputtering) and surface track formation. The experimental techniqu
|
|
| 9. |
- Enger, Shirin A., et al.
(författare)
-
Dosimetry for gadolinium neutron capture therapy (GdNCT)
- 2013
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1879-0925 .- 1350-4487. ; 59, s. 233-240
-
Tidskriftsartikel (refereegranskat)abstract
- Background Gadolinium (Gd) neutron capture therapy (GdNCT) is based on a neutron capture reaction (NCR) that involves emission of both short and long range products. The aim of this study was to investigate both the microscopic and macroscopic contributions of the absorbed dose involved in GdNCT. Methods Cylindrical containers with diameters 1-30 mm filled with a solution of Gd were irradiated with epithermal neutrons. The background neutron dose as well as the prompt gamma dose has been calculated and measured by means of film dosimetry for the largest cylinder. Monte Carlo codes MCNP5(b) and GEANT4 have been utilized for calculation the absorbed dose. Results and discussion Results from the film dosimetry are in agreement with the calculations for high doses while for low doses the measured values are higher than the calculated results. For the largest cylinder, the prompt gamma dose from GdNCR neutron is at least five times higher than the background dose. For a cell cluster model, in the first 0.1 mm the major contribution to the absorbed dose is from IC electrons. If Gd atoms were homogeneously distributed in the nuclei of all tumour cells, capture events between neutron and Gd atoms close to DNA could kill the tumour cells and give cross-fire dose from IC electrons to the cells located in the 0.1 mm range. Conclusions For a correct GdNCT dosimetry both microscopic part of the dose delivered by short-range low energy electrons and macroscopic part delivered by the prompt gamma should be considered.
|
|
| 10. |
- Ersmark, T., et al.
(författare)
-
Influence of geometry model approximations on Geant4 simulation results of the Columbus/ISS radiation environment
- 2007
-
Ingår i: Radiation Measurements. - : Elsevier BV. - 1350-4487 .- 1879-0925. ; 42, s. 1342-1350
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of geometry model approximations on Geant4 Monte Carlo simulation results of the radiation environment on-board the Columbus module of the International Space Station (ISS) has been investigated. Three geometry models of Columbus with different levels of detail and a geometry model of ISS have been developed. These geometries have been used for Geant4 simulations of the radiation environment inside Columbus induced by trapped protons and Galactic Cosmic Ray protons. Simulated dose rates and particle spectra on-board Columbus for each of the three Columbus models, with or without the ISS geometry model included, are presented and compared. From comparisons of simulated dose rates and particle spectra for the three different geometry models it was found that the most detailed geometry model (750 volumes) produced results similar to a much less detailed model (23 volumes). The most detailed geometry model was concluded to be a sufficiently detailed approximation of the physical Columbus for the purpose of proton induced space radiation studies. The simulated dose rates are compatible with measurements on-board the ISS. The simulation results also show that an increase in shielding thickness decreases the simulated dose rate induced by trapped protons. For Galactic Cosmic Ray protons the dose rate remains unchanged or is slightly increased.
|
|
