Monitoring the ambient dose equivalent rate at aviation altitudes is an ambitious task, which requires sophisticated dosemeter systems and the possibility to carry out such measurements on board ...aircraft. A rather simple approach has been investigated in this study: soundings with weather balloons up to an altitude of 30 km. This paper summarises the measurements carried out between 2011 and 2016. The results indicate that annual measurements of the ambient dose equivalent rate at altitudes of around 20 km are a reliable tool to monitor the variation of the dose rate in the atmosphere owing to the solar activity.
Dosimetry at aviation altitudes requires instruments that are able to measure the dose contributions of all field components. Tissue-equivalent proportional counters (TEPCs) are well suited for this ...task. From the measured lineal energy distribution, the absorbed dose and the dose equivalent can be obtained. The ratio of both quantities is named the quality factor, which is a measure of the biological effectiveness of the radiation field. The results of this work show that the mean quality factors obtained by using a TEPC are independent of the altitude, at least at altitudes between flight level (FL) 300 and FL 400, but show a significant dependence on the vertical cutoff rigidity. From a numerical simulation of the radiation field inside an aircraft, the influence of the aircraft structure can be shown.
Dosimetric measurements in the field of secondary cosmic radiation were extensively made during the last years. Since the majority of these measurements were performed on-board passenger aircraft at ...altitudes between 10 and 12 km, measurements at higher altitudes are desirable for the verification of the legal dose assessment procedures for aircrew. A simple solution is to use a high-altitude balloon that reaches altitudes as high as 30 km. In this work, it is shown that the dose rate profile up to 30 km can be measured with acceptable uncertainties using a Si-detector.
To investigate and monitor environmental radiation at ground level, Physikalisch-Technische Bundesanstalt (PTB) has installed several dosemeters and particle detectors at the new Ambient Radiation ...Dosimetry Site. The separation of the total ambient dose equivalent rate \batchmode \documentclassfleqn,10pt,legalpaper{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \({\dot{H}}^{{\ast}}\left(10\right)_{\mathrm{env}}\) \end{document} of environmental radiation into the different contributions is achieved by comparing the data of different detectors: the muon detector MUDOS, a modified neutron dosemeter, proportional counters and ionisation chambers. The response of the latter two dosemeter systems to cosmic radiation was determined at the Cosmic Radiation Dosimetry Site on a lake near PTB. Besides the increase of the ambient dose equivalent rate during rainfall, variations owing to air pressure, solar activity and temperature changes in the upper atmosphere are observed. Without rain and solar effects, smooth variations of the cosmic component at ground level of ±6.9 nSv h−1 should be treated as naturally occurring variations during an entire year.
Monitoring the radiation field at aviation altitudes is achieved by the dosemeter system πDOS installed in a passenger aircraft. The basic detector is a 2 in. tissue-equivalent proportional counter ...(TEPC) mounted in a cabin-baggage-sized aluminium suitcase. The entire system was characterised in neutron and photon reference fields from which two calibration factors were determined according to the splitting of the measured dose deposition spectrum yd(y) into low-LET and high-LET regions. A total of 255 flights in the northern hemisphere was analysed. The dependencies of the ambient dose equivalent rates on altitude, latitude and solar activity have been determined. These new data extend the data base used in Germany for the validation of program codes to calculate the radiation exposure of air crew members.
The European Commission has funded within its 6th Framework Programme a three-year project (2005–2007) called CONRAD,
COordinated Network for RAdiation Dosimetry. The organizational framework for ...this project was provided by the European radiation Dosimetry Group EURADOS. Work Package 6 of CONRAD dealt with “
complex mixed radiation fields at workplaces” and in this context it organised a benchmark exercise, which included both measurements and calculations, in a stray radiation field at a high-energy particle accelerator at GSI, Germany. The aim was to intercompare the response of several types of active detectors and passive dosemeters in a well-characterised workplace field. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers are discussed in Rollet et al. (2008) and in Wiegel et al. (2008). This paper focuses on the intercomparison of the response of the dosemeters in terms of ambient dose equivalent. The paper describes in detail the detectors employed in the experiment, followed by a discussion of the results. A comparison is also made with the
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(10) values predicted by the Monte Carlo simulations and those measured by the BSS systems.
Intercomparisons of dosemeters used in radiation protection are performed routinely in reference radiation fields under well-defined conditions. In the case of the radiation protection of aircrew ...members, such reference fields either do not exist or they can be partially simulated by accelerator-based fields. Another method is to perform simultaneous measurements on board an aircraft under constant flight conditions, i.e. at defined latitude, longitude and altitude. The intercomparison presented in this work is the second one of its kind. As reference instruments, two types of tissue-equivalent proportional counters (TEPC) were used in comparison with different silicon detector systems. The excellent agreement of the FDOScalc code, which is based on measurements made by PTB during different phases of solar cycle 23 with the TEPC measurements and the results of the preceding project “Coordinated Access to Aircraft for Transnational Environmental Research” (CAATER) even allows the in-field calibration of the Si dosemeters.
Within the framework of the EURADOS Working Group 11, a comparison of passive neutron dosemeters in high-energy neutron fields was organised in 2011. The aim of the exercise was to evaluate the ...response of poly-allyl-glycol-carbonate neutron dosemeters from various European dosimetry laboratories to high-energy neutron fields. Irradiations were performed at the iThemba LABS facility in South Africa with neutrons having energies up to 66 and 100 MeV.
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