Intrinsic background of the beta channel of the aerosol volumetric activity monitor

The work is devoted to the study of the features of generation of the intrinsic background of the measuring beta channel of the aerosol monitor in real conditions of measuring the volumetric activity of aerosols, caused by radionuclides of technogenic origin. The influence of external factors on the generation of the level of the intrinsic background of the measuring channel of the monitor and its metrological characteristics is investigated. The reliability of the results of measurements of the volumetric activity of air aerosols substantially depends on the correct accounting of external factors, parameters of the monitored environment and the specified operating mode of the monitor. Aerosol volumetric activity monitors, as a rule, operate in a continuous mode, in which the aspiration method of aerosol accumulation is implemented, followed by measuring the volumetric activity of aerosols by alpha radiation and (or) beta radiation generated by technogenic radionuclides. This article describes the results of experiments on measuring the iCAM aerosol monitor’s intrinsic beta channel background under real operating conditions, and its dependence on external factors. The studies were carried out on iCAM aerosol monitors (iCAM/D and iCAM/MF modifications) manufactured by Canberra Industries Inc. in a laboratory room in normal climatic conditions with a radon volumetric activity of 35±10 Bq·m-3 and an equivalent dose rate of gamma radiation of 0.13±0.02 μSv·h-1. In modern aerosol monitors, software and hardware solutions are implemented that allow to significantly reduce the background level and, as a result, to expand the measurement range of the volumetric activity of aerosols towards low values.

Dynamic of Particulate Matter for Quotidian Aerosol Sources in Indoor Air

A correlation between the mass concentration of particulate matter (PM) and the occurrence of health-related problems or diseases has been confirmed by several studies. However, little is known about indoor PM concentrations, their associated risks or their impact on health. In this work, the PM1, PM2.5 and PM10 produced by different indoor aerosol sources (candles, cooking, electronic cigarettes, tobacco cigarettes, mosquito coils and incense) are studied. The purpose is to quantify the emission characteristics of different indoor particle sources. The mass concentration, the numerical concentration, and the size distribution of PM from various sources were determined in an examination room 65 m3 in volume. Sub-micrometer particles and approximations of PM1, PM2.5 and PM10 concentrations were measured simultaneously using a diffusion aerosol spectrometer (DAS). The ultrafine particle concentration for the studied indoor aerosol sources was approximately 7 × 104 particles/cm3 (incense, mosquito coils and electronic cigarettes), 1.2 × 105 particles/cm3 for candles and cooking and 2.7 × 105 particles/cm3 for tobacco cigarettes. The results indicate that electronic cigarettes can raise indoor PM2.5 levels more than 100 times. PM1 concentrations can be nearly 55 and 30 times higher than the background level during electronic cigarette usage and tobacco cigarette burning, respectively. It is necessary to study the evaluation of indoor PM, assess the toxic potential of internal molecules and develop and test strategies to ensure the improvement of indoor air quality.

SEISMICITY of the KOPETDAG REGION in 2015

In 2015, the seismicity of the Kopetdag region was monitored by the network of 32 seismic stations, including 28 digital and 4 analogue stations. The re-equipment of stationary analogue stations of Turkmenistan with digital GEOSIG equipment, which began in 2013, was continued in 2015 – 6 GEOSIG stations were added to 9 stations of this type, and the analogue equipment at the re-equipped stations was stopped. In 2015, the seismic activity A10 in the Kopetdag region was close to the background level for the period 1992–2014, while the number of weak events significantly exceeded the level of the previous year. The seismic activation along the boundaries of the crustal blocks in the north of the Iranian plate, which began in 2012, continued by the October 12, 2015 earthquake with KR=12.7, Mw=5.2. This strongest earthquake in the territory of Turkmenistan in 2015, named the Kenekesir earthquake by the name of the nearest settlement, accompanied by numerous aftershocks – more than 35000 events with KR=3–11 were located during 80 days after the mainshock within 30 km radius. The aftershock series lasted 186 days and ended in 2016. According to the complex of instrumental seismological and tectonic data, oblique-slip with equal normal and strike-slip components occurred in the source of the mainshock. The rupture plane had a southwestern strike and dipped to the northwest. The maximum ("Bath’s") aftershock occurred on November 16 with KR=11.1. Judging by its remoteness from the mainshock in space and time, and the difference in the type of movement in the source (upthrust), it was caused by stress relaxation in the environment.

SEISMICITY of AZERBAIJAN and ADJACENT TERRITORIES in 2015

In 2015, the network of Azerbaijan seismic stations included 35 digital stations, which continued to operate unchanged. The set of parameters determined for estimating the earthquake magnitude has decreased – determination of the MPVA magnitude and КР energy class has ceased. Only the local magnitude MLАзр was measured. The total number of earthquakes recorded by the Azerbaijan network of stations in 2015 amounted to 6419, however, only 128 of them with MLАзр3.0 are given in the catalogue of earthquakes of Azerbaijan published in the Appendix to this article. Seismic activity in the study area remained unchanged. The released seismic energy changed insignificantly compared to its value in 2014 and was close to the background level for the period 1993–2014. The increase in the number of earthquakes of the representative level (K≥8.6, MLАзр≥2.8) in comparison with the long-term average annual value is due to aftershocks of earthquakes on January 26 with MLАзр=4.9, June 3 with MLАзр=4.6, and September 4 with MLАзр=5.9. The 2015 most significant seismic event on the territory of the Republic was the earthquake on September 4 with MLАзр=5.9 and seismic intensity at the epicenter of I0=7.

Single Particle Detection System for Strong-Field QED Experiments

Measuring signatures of strong-field quantum electrodynamics (SF-QED) processes in an intense laser field is an experimental challenge: it requires detectors to be highly sensitive to single electrons and positrons in the presence of the typically very strong x-ray and γ-photon background levels. In this paper, we describe a particle detector capable of diagnosing single leptons from SF-QED interactions and discuss the background level simulations for the upcoming Experiment-320 at FACET-II (SLAC National Accelerator Laboratory). The single particle detection system described here combines pixelated scintillation LYSO screens and a Cherenkov calorimeter. We detail the performance of the system using simulations and a calibration of the Cherenkov detector at the ELBE accelerator. Single 3 GeV leptons are expected to produce approximately 537 detectable photons in a single calorimeter channel. This signal is compared to Monte-Carlo simulations of the experiment. A signal-to-noise ratio of 18 in a single Cherenkov calorimeter detector is expected and a spectral resolution of 2% is achieved using the pixelated LYSO screens.

Environmental Assessment in the Pre-launch Phase of Hayabusa2 for Safety Declaration of Returned Samples From Asteroid (162173) Ryugu: Background Monitoring of Possible Contaminants During Development of the Sampler System

We report the ground-based environmental assessments during development of the sampler system until the launch of the Hayabusa2 spacecraft. We conducted static monitoring of potential contaminants to assess the environmental cleanliness during (1) laboratory work throughout the development and manufacturing of the sampler devices, (2) installation of the sampler system on the spacecraft, and (3) transportation to the launch site at the JAXA’s Tanegashima Space Center. Major elements and ions detected in our inorganic analysis were sodium (Na), potassium (K), and ionized chloride (Cl–); those were positively correlated with the total organic content and with exposure duration in the range from 101 to 103 nanogram per monitor coupon within a ~30 mm-diameter scale. We confirmed that deposits on the coupon were totally less than the microgram-scale order during manufacturing, installation, and transportation in the pre-launch phase. The present assessment yields a nominal safety declaration for sample analysis of the pristine sample (>5 g) returned from asteroid (162173) Ryugu combined with a highly clean environmental background level. We expect that the Hayabusa2-returned sample from Ryugu without severe and/or unknown contamination will allow us to provide native profiles recorded in the carbonaceous asteroid history.

Analysis of Structures’ Orientations in Archaeoastronomy

In the scope of archaeoastronomy, the analysis of a large number of structures through the frequency histograms for their azimuths and declinations can identify singular patterns of orientation. Conclusions often rely on qualitative assessments. Quantitative assessments have been proposed by using as null hypothesis a pure random distribution of azimuths over the 360º horizon. In some cases, such as orientation of Christian churches, the histograms or spectra are composite, with peaks overlapping a continuous and not uniform background. This paper presents a methodology for assessing the statistical significance of the net area of a peak in the histogram in relation to the local background level. The spectra use Normal kernel functions. The background contribution is estimated from the area of the trapezoidal polygon under the peak, and it is interpreted as the probability parameter for a Binomial distribution. The methodology is illustrated with a real case study which includes the azimuth and declination histograms for a set of churches from southern Spain dedicated to the Virgin of the Assumption. The method is more restrictive than previous approaches.

The need to review low-dose decision-making in radiation protection

The current approach in the system of protection, and the way in which it is implemented in regulation and practical application, has resulted in the allocation of significant and disproportionate societal resources to reduce relatively low-level exposures to even lower levels. The resulting exposure levels are often a fraction of the basic natural background level, and in particular are comparable to, or often significantly less than, the variability of natural background exposures due to individual decision-making, which the system of protection deems acceptable. There are arguments for a wider approach to decision-making at such low doses, recognising the uncertainties in radiation risk estimation and acknowledging the context that all human life takes place in a variable natural background radiation which generally dominates these lower dose exposures. Recommendations are presented for improvements in how decisions are made in controlling low doses.

Environmental contamination with metals as a risk factor causing developing autoimmune thyroiditis in children in zones influenced by emissions from metallurgic enterprises

Chemical environmental factors trophic for the endocrine system and its organs produce negative influence on it that becomes apparent through growing incidence and pathomorphism of endocrine diseases. Our test group was made up of 102 children with diagnosed autoimmune thyroiditis (AIT) who were chronically exposed to metals (lead, manganese, nickel, chromium, and zinc) being components in emissions from metallurgic enterprises in Perm region. Our reference group included 46 children with AIT who lived beyond zones influenced by the aforementioned enterprises in areas with the sanitary-hygienic situation being relatively favorable. We comparatively analyzed the results of clinical and ultrasound examinations that focused on evaluating children’s thyroidal and immune state. A growth in incidence with thyroiditis amounted to 63.6 % on the test territory over 10 years and it was 1.6 times higher than on average in the region (40.8 %); there was no growth in the indicator detected on the reference territory. Concentrations of chromium, nickel, lead, zinc, and manganese higher than regional background level were 1.7–5.5 times more frequently detected in blood of children from the test group against the reference one. A number of AIT cases was higher among exposed boys (by 2.0 times, p = 0.070); exposed children also had higher Ig A, M, and G contents in blood serum (by up to 2.9 times, p = 0.015–0.056), higher TSH levels (by 2.0 times, p = 0.096), and lower free T4 contents (by 5.4 times, p = 0.057). Diffuse damage to the thyroid gland was by 1.3 times more frequent under exposure to adverse factors created by metallurgic production; AIT combined with other diseases was also more frequent (p = 0.041). Rates and growth in incidence of thyroid gland diseases and thyroiditis are by 1.3–2.3 times higher among children and teenagers living on territories where metallurgic enterprises are located against the same indicators on territories where sanitary-hygienic situation is relatively favorable. We detected less apparent gender-related differences in AIT frequency, a greater number of improper thyroidal state, elevated risks of diffuse changes in the thyroid gland and activation of humoral immune response that was by 2.2–3.4 times more frequent together with concomitant damage to other systems under elevated contents of metals in blood.

An Integrated System for Simultaneous Monitoring of Traffic and Pollution Concentration—Lessons Learned for Bielsko-Biała, Poland

The challenge of maintaining the required level of mobility and air quality in cities can be met by deploying an appropriate management system in which the immediate vicinity of roads is monitored to identify potential pollution hotspots. This paper presents an integrated low-cost system which can be used to study the impact of traffic related emission on air quality at intersections. The system was used for three months in 2017 at five locations covering intersections in the centre of a mid-sized city. Depending on the location, pollution hotspots with high PM2.5 and PM10 concentrations occurred 5–10% of the time. It was shown that despite the close mutual proximity of the locations, traffic and the immediate surroundings lead to significant variation in air quality. At locations with adverse ventilation conditions a tendency towards more frequent occurrences of moderate and sufficient air quality was observed than at other locations (even those with more traffic). Based on the results, a practical extension of the system was also proposed by formulating a model for the prediction of PM2.5 concentration using a neural network. Information on transit times, meteorological data and the background level of PM10 concentration were used as model input parameters.