REFLECT – Research flight of EURADOS and CRREAT: Intercomparison of various radiation dosimeters onboard aircraft

Aircraft crew are one of the groups of radiation workers which receive the highest annual exposure to ionizing radiation. Validation of computer codes used routinely for calculation of the exposure due to cosmic radiation and the observation of nonpredictable changes in the level of the exposure due to solar energetic particles, requires continuous measurements onboard aircraft. Appropriate calibration of suitable instruments is crucial, however, for the very complex atmospheric radiation field there is no single reference field covering all particles and energies involved. Further intercomparisons of measurements of different instruments under real flight conditions are therefore indispensable. In November 2017, the REFLECT (REsearch FLight of EURADOS and CRREAT) was carried out. With a payload comprising more than 20 different instruments, REFLECT represents the largest campaign of this type ever performed. The instruments flown included those already proven for routine dosimetry onboard aircraft such as the Liulin Si-diode spectrometer and tissue equivalent proportional counters, as well as newly developed detectors and instruments with the potential to be used for onboard aircraft measurements in the future. This flight enabled acquisition of dosimetric data under well-defined conditions onboard aircraft and comparison of new instruments with those routinely used. As expected, dosimeters routinely used for onboard aircraft dosimetry and for verification of calculated doses such as a tissue equivalent proportional counter or a silicon detector device like Liulin agreed reasonable with each other as well as with model calculations. Conventional neutron rem counters underestimated neutron ambient dose equivalent, while extended-range neutron rem counters provided results comparable to routinely used instruments. Although the responses of some instruments, not primarily intended for the use in a very complex mixed radiation field such as onboard aircraft, were as somehow expected to be different, the verification of their suitability was one of the objectives of the REFLECT. This campaign comprised a single short flight. For further testing of instruments, additional flights as well as comparison at appropriate reference fields are envisaged. The REFLECT provided valuable experience and feedback for validation of calculated aviation doses

Influence of vitamin D3 analogues in combination with budesonid R on proliferation of nasal polyp fibroblasts

Vitamin D (VD) and its different analogues, besides their classic role as regulators of calcium and phosphor homeostasis, have emerged as a large family of antiproliferative agents. Such properties suggested VD potential as a therapy for chronic inflammatory diseases, including nasal polyposis (NP). NP growth involves both an inflammatory process and the proliferation of fibroblast as an important factor inducing aberrations in the phenotype of the epithelium. The aim of this study was to investigate the possible influence of 1α,25-dihydroxyvitamin D3 (calcitriol) and 1α,24(R)-dihydroxyvitamin D3 (tacalcitol) in monotherapy and in combination with budesonid R (BR) on NP fibroblast proliferation. Material and methods: The study involved 26 samples of NP. NP cells were cultured on 96-well plates beginning with a concentration of 5 × 103 cells per well with RPMI 1640 medium supplemented with antibiotics and 10% foetal bovine serum. After the fourth to sixth passage the medium was replaced with a nutrient medium with calcitriol or tacalcitol in a defined concentration (from 10-9 M to 10-3 M) alone or in combination with BR in 1:1, 1:3 or 3:1 ratios, each at concentrations from 10-5 M to 10-3 M. Results: Growth inhibition of nasal fibroblasts exposed to calcitriol or tacalcitol was noted. Significant antiproliferating activity was observed at calcitriol concentrations of 10-4 M and 10-3 M after 48 h, and at a concentration of 10-3 M after 72 h with the percentage of proliferating cells reduced to 30% compared to the control samples (P < 0.05). In cells treated with tacalcitol the maximal effect was seen at 10-4 M after 48 h and at 10-3M after 72 h with a 60% inhibition with respect to the control (P < 0.05). The inhibition of fibroblast proliferation reached the maximal level when they were exposed to calcitriol: BR (1 : 1) or tacalcitol: BR (1 : 1), each at a concentration of 10-4 M, after 72 h (82% and 69%, respectively). Conclusions: The antiproliferative activity of calcitriol and tacalcitol in NP cultures was confirmed. Because of its lower toxicity and higher activity tacalcitol seems to be the more promising agent in NP therapy, both as a single medication and in treatment protocols with BR

Microdosimetric GEANT4 and FLUKA Monte Carlo simulations and measurements of heavy ion irradiation of silicon and tissue

We describe microdosimetric measurements and simulations with Geant4 and FLUKA Monte Carlo codes in silicon and tissue. Analyses of deposited energy in sensitive volumes of some micrometers were carried out after exposure to heavy ion radiatio

Investigations on Photon Energy Response of RadFET Using Monte Carlo Simulations

International audienceWe describe investigations of RadFET energy response simulated with Geant4 and FLUKA2005 Monte Carlo codes. An analysis of energy deposition is carried out for photon irradiation with energies between 35 keV and 2 MeV. The absorbed dose in the silicon dioxide layer (few hundred nanometers) is compared for both transport codes

Radiation evaluation of digital isolators for space applications

Recently we presented preliminary results on TID and SEE testing of digital isolators. In this paper, we give a comprehensive summary of radiation-hardness characterization for three digital isolator’s technologies. Further, we provide overall conclusions on their suitability for space applications and give recommendations on further investigations

MATSIM: Development of a Voxel Model of the MATROSHKA Astronaut Dosimetric Phantom

The AIT Austrian Institute of Technology coordinates the project MATSIM (MATROSHKA Simulation) in collaboration with the Vienna University of Technology and the German Aerospace Center, to perform FLUKA Monte Carlo simulations of the MATROSHKA numerical phantom irradiated under reference radiation field conditions as well as for the radiation environment at the International Space Station (ISS). MATSIM is carried out as co-investigation of the ESA ELIPS projects SORD and RADIS (commonly known asMATROSHKA), an international collaboration of more than 18 research institutes and space agencies from all over the world, under the science and project lead of the German Aerospace Center. During MATSIM a computer tomography scan of the MATROSHKA phantom has been converted into a high resolution 3-dimensional voxel model. The energy imparted and absorbed dose distribution inside the model is determined for various radiation fields. The major goal of the MATSIM project is the validation of the numerical model under reference radiation conditions and further investigations under the radiation environment at ISS. In this report we compare depth dose distributions inside the phantom measured with thermoluminescence detectors (TLDs) and an ionization chamber with FLUKA Monte Carlo particle transport simulations due to Co-60 photon exposure. Further reference irradiations with neutrons, protons and heavy ions are planned. The fully validated numerical model MATSIM will provide a perfect tool to assess the radiation exposure to humans during current and future space missions to ISS, Moon, Mars and beyond

Development of a Miniaturized Reference Dosimeter Payload for SmallSat Applications

We present the TID Reference Dosimeter and SEU Assessment System, an autonomous, miniaturized dosimetry payload for SmallSat applications. We provide information on the concept, performance and the current status of its development, including preparations for the payload’s first in-orbit demonstration onboard the Austrian CubeSat PRETTY