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Validation of electromagnetic and hadronic physical processes in the interaction of a proton beam with matter: A Solar Particle Events case study with an Al slab
No full textn the study of the effectiveness of shielding materials against radiations, one of the main steps concerns with the validation of models describing the interaction processes of the radiation of interest with the material chosen for the shielding. This paper shows the results of the validation of electromagnetic and hadronic processes with the aim to contribute to the study of protection for astronauts against the radiations due to the Solar Particle Events, in particular to the selection of the optimal material for radiation shielding. The physics case deals with the interaction of a proton beam with an aluminum slab about 20 g/cm2 thick. Two specific applications, STP and DOSE, were developed by using Geant4 package. STP computes the radiations produced in the interaction and their stopping power; DOSE computes the absorbed dose from the stopping power calculated by STP. The validation process was performed in two steps. In the first one, the output of the STP code is compared to data available on NIST database; in the second one, the absorbed dose computed with DOSE is compared to the dose gathered during an experiment performed at the NASA Space Radiation Laboratory involving the bombardment of an aluminum slab with a 1 GeV proton beam. The computing model has allowed us to correlate the size of the impinging beam profile to the dose measured before and after an Al slab. The sharp increase of the dose in the position right after the slab might be due to the stochastic nature of the trajectories of charged ions in matter which makes the radiation to emerge with non-zero transverse linear momentum. From the case examined here, we conclude that aluminum is not an efficient material for Solar Particle Event shielding
RADON MEASUREMENTS AND EFFECTIVE DOSE FROM RADON INHALATION ESTIMATION IN THE NEAPOLITAN CATACOMBS
No full textIn this study, the indoor radon activity concentrations have been measured in the Neapolitan catacombs using LR115 detectors. The detectors were exposed for two quarters, one in the warm season and the other in the cold. This has allowed one to evaluate the seasonal variations of concentrations, while the diurnal variations were evaluated performing continuous measurements by a Radim 5 monitor. The authors found that radon concentrations were lower in winter than in summer. Based on their values, taking into consideration the working hours in the catacombs and the equilibrium factor of 0.4, the effective dose to workers was estimated
INDOOR RADON CONCENTRATION MEASUREMENTS IN SOME DWELLINGS OF THE PENISOLA SORRENTINA, SOUTH ITALY
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Indoor radon exposure and lung cancer risk: a meta-analysis of case-control studies
Full text linkThe aim of this study was to assess a potential relationship between indoor radon exposure and
the incidence of lung cancer worldwide. A systematic literature search was carried out in PubMed, Web of
Science, and Google Scholar to identify relevant studies published in English conducted in the last 15 years
until January 2016. Summary relative risks (RR) and the corresponding 95% confidence intervals (CIs)
were calculated using a random-effects model and the influence of moderators using a mixed-effects model.
Heterogeneity was assessed using the Q, I2 and H2 tests, and the source of heterogeneity was detected by
meta-regression analysis. Publication bias was evaluated with Egger’s regression symmetry test and the
contour-enhanced funnel plot. Leave-one-out sensitivity analysis was performed. Twenty-five lung cancer
studies (case-control studies) with 13,569 cases and 22,701 controls were included. Indoor Radon exposure
was significantly associated with increased risk for lung cancer (RR, 1.19; 95% CI, 1.02–1.39). Study location
analysis showed that radon exposure was associated with increased risk for lung cancer from forty degrees
absolute latitude (RR, 1.09; 95% CI, 0.92–1.31), to fifty degrees (RR 1.26; 95% CI, 1.08–1.48), to sixty
degrees (RR, 1.46; 95% CI, 1.12–1.91). Indoor radon exposure may be associated with increased risk for lung
cancer
Indoor radon concentration and gamma dose rate in dwellings of Province of Naples, South Italy and their radiological impact on the population
No full textThe indoor radon concentration was measured in 471 dwellings in the Province of Naples. Radon concentration
measurements were carried out using LR-115 passive alpha track detectors (SSNTDs) that were exposed
for two consecutive semesters. The annual average radon concentration in the dwellings was found to vary from 21
to 722 Bq m−3 with an average value of 107 ± 75 Bq m−3. In about 93% of the dwellings the radon concentrations
were found to be below 200 Bq m−3, which is the recommended level by Italian law for new buildings. Simultaneously
with the radon concentration measurements, indoor gamma dose rates were measured in 388 dwellings. Indoor gamma
dose rates were measured using Thermoluminescent Dosimeters (TLDs) exposed in each dwelling for six months. The
arithmetic mean value was found to be 327 ± 102 nGy h−1, after the subtraction of the cosmic ray contribution. A weak
correlation between the indoor radon concentration and gamma dose rate was found. The correlation between indoor
radon measurements and gamma dose rates and the same building characteristics was also studied
Results of nDOSE and HiDOSE Experiments for Dosimetric Evaluation During STS-134 Mission
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The assessment of space radiation exposure of biology experiments during two short-term missions
No full textThe assessment of space radiation exposure on plants, animals, cell cultures, as well as the astronauts, is crucial not only because it is very different from that to which they are subjected on the earth, but also to understand the combined effects of exposure to space radiation under microgravity. In particular, we evaluated the equivalent dose due to neutrons and charged particles for biology experiments, in two short-term missions, FOTON M3 and STS-34 mission, using Thermo Luminescence Dosimeters (TLDs) to evaluate the charged particles dosimetry and a set of passive neutron bubbles detectors for neutron dosimetry. In STS-34 mission, stack bismuth track dosimeter was used in addition to bubbles detectors to evaluate the dose equivalent rate due to neutrons in a wide energy range (0.025 eV-200 GeV). Considering a total dose due to both radiation types particles, a value of about 1 mSv/day is obtained. The neutron component represents about 18 of the total
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