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This paper presents an interlaboratory comparison of radiated emission measurements in the frequency range of 30-1000 MHz. A tubular dipole was specifically designed and employed as a reference emitting source. The most important for a tubular dipole is stability in the testing process. The stability is not the performance of the sample, but the emission signal of the sample is stable. In addition, two ways of determining the reference value of the electromagnetic field strength are considered. The first reference value is obtained by using robust analysis. It is a robust average value that is calculated by averaging the measurement results provided by the participating testing laboratories. The other reference value is obtained through the simulation-experimental results of the tubular dipole in the semi-anechoic chamber or full anechoic chamber, for horizontal and vertical polarizations and 3 m distance measurement, respectively. In addition, this value is assigned by the coordinator. Measurement results are compared using the robust z-scores and -scores, respectively.

The paper represents the results of testing the effect of neutron and gamma radiation of radioactive 60Co on electrical filters. Neutron and gamma radiation was chosen because of its conductivity. The analysis of the standard structure of the electric filter found that neutron and gamma radiation can affect the value of the capacitance as the most important component of the filter. The presented results are a contribution to the wider research of the radiation resistance of elements for the coordination of insulation at the low-voltage level. The experiments were performed on commercial capacitors that are installed in electric filters. Measurements were made with professional equipment under well-controlled laboratory conditions. The combined measurement uncertainty of the experimental procedure was less than 5%.

This paper considered the possibility of reducing the dissipation of the trigger time of the three-electrode spark gaps with a separated triggered electrode. The work is of a theoretical, numerical and of experimental nature. The experiments were performed on a spark gap model under well-controlled laboratory conditions. It was determined that the results obtained with the model can be applied to the spark gap prototype. Unlike the previous research in this area, the computer-designed spark gap that was used can be triggered with one mechanism only. Also, as opposed to the previous study, a mixture of SF6 and He gases and the third electrode with a double ionization effect were used. The obtained results showed the optimal combination of the construction solution, insulation gas, triggered impulse, and the triggered electrode's shape, reduce the stochastic dissipation of a random variable far in the sub-microsecond field. This result is of great significance for the parallel triggering of current and voltage generators to obtain the best superposition signals.

The possibility of the classical response rate engineering and the long-term deconditioning of the gas-filled surge arresters is considered in this paper. The obtained results are compared with the same results obtained with the gas-filled surge arrester with application of an alpha radioactive source. The work is of an experimental nature. Experiments were performed on the multipurpose gas-filled surge arrester model under well-controlled conditions. The measurement uncertainty of the experimental procedure was less than 8 %. The results were processed by statistical data processing software. To draw impulse characteristics, the law of constancy of surfaces below the impulse voltage in the volt-second area, was used.

The aim of this paper is to examine the influence of the magnetic field shape in the inter-contact space in the context of contact degradation during the switching operation of circuit-breaking with current. The results of measuring the AC breakdown voltage and pulse breakdown voltage are statistically analyzed for that purpose. The experiments are carried out on the commercial switching elements with CuCr contact. The experiment parameters are the current breaking voltage value and inter-electrode distance. Results showed that switches with radial magnetic field suffer less irreversible changes during the breaking operation such as circuit-breaking with nominal current and circuit-breaking with short-circuit current.

In recent testing of the partial discharges or the use for the diagnosis of insulation condition of high voltage generators, transformers, cables and high voltage equipment develops rapidly. It is a result of the development of electronics, as well as, the development of knowledge about the processes of partial discharges. The aim of this paper is to contribute the better understanding of this phenomenon of partial discharges by consideration of the relevant physical processes in isolation materials and isolation systems. Prebreakdown considers specific processes, and development processes at the local level and their impact on specific isolation material. This approach to the phenomenon of partial discharges needed to allow better take into account relevant discharge parameters as well as better numerical model of partial discharges.

This work presents the results of an investigation undertaken to determine the level of natural radioactivity in the traditional building materials used for medieval indoor vaulted constructions in the territory of the central Balkan region. Indoor radiation exposure varies appreciably if it comes from the earth building materials, hence the presence of natural radioisotopes of 226Ra, 232Th, and 40K in masonry vaulted constructions was analyzed using gamma ray spectrometry. In addition, the internal health hazard index, the absorbed dose rates and the effective annual doses were calculated. The results were then compared both with the reported data from the previous studies concerning the territory of the Balkan Peninsula, as well as with the worldwide values for the materials of historic buildings. The results obtained from the materials examined in this paper all showed the radioactivity levels below the maximum permitted values. [Projekat Ministarstva nauke Republike Srbije, br. 171007 i br. 43009]

A method for approximate analytical solution of transport equation for particles in plane geometry is developed by solving Fredholm integral equations. Kernels of these equations are the Green's functions for infinite media treated approximately. Analytical approximation of Green's function is based on decomposition of the functions into terms that are exactly analytically solved and those which are approximately obtained by usual low order DPN approximation. Transport of particles in half-space is treated, and reflection coefficient is determined in the form of an analytical function. Comparison with the exact numerical solution and other approximate methods justified the proposed analytical technique. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

This paper presents results of radiation resistance of different types of commercially available single- and poly-crystalline silicon solar cells. Sample cells were subjected to gamma radiation from gamma radiation source 60Co. Characteristic parameters of solar cells were extracted from obtained I-V curves: open circuit voltage, short circuit current, maximum power point voltage and current, efficiency, fill factor, and series resistance. Obtained results show the level of parameters' degradation with purpose of increasing solar cells applications in radiation environments. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

This paper investigates the output characteristics of photovoltaic solar cells working in hostile working conditions. Examined cells, produced by different innovative procedures, are available in the market. The goal was to investigate stability of electric characteristics of solar cells, which are used today in photovoltaic solar modules for charging rechargeable batteries which, coupled with batteries, supply various electronic systems such as radio repeaters on mountains tops, airplanes, mobile communication stations and other remote facilities. Charging of rechargeable batteries requires up to 25 % higher voltage compared to nominal output voltage of the battery. This paper presents results of research of solar cells, which also apply to cases in which continuous power supply is required. [Projekat Ministarstva nauke Republike Srbije, br. III 171007]

Positron emission tomography is a technology that provides unique and exquisite possibilities in functional diagnostics, in the sense that it is the most efficient and most reliable method for obtaining information about biochemical activity and cellular metabolism in the body, by determining exact localization and performing semi-quantitative assessment of the distribution of a radioactive tracer. This paper compares the characteristics of recently introduced lutetium based crystals to those of conventionally used bismuth-ortho-germanate scintillators; both options are used as scintillation detectors within the positron emission tomography systems. Energy resolution and scintillation decay time of lutetium based crystals and bis-muth-ortho-germanate crystals was experimentally tested. Main scintillation detector parameters which affect the resulting detector response are considered and analyzed, since they serve as the basis for a positron emission tomography medical image. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

Electromagnetic radiation of all frequencies represents one of the most common and fastest growing environmental influence. All populations are now exposed to varying degrees of electromagnetic radiation and the levels will continue to increase as technology advances. An electronic or electrical product should not generate electromagnetic radiation which may impact the environment. In addition, electromagnetic radiation measurement results need to be accompanied by quantitative statements about their accuracy. This is particularly important when decisions about product specifications are taken. This paper presents an uncertainty budget for disturbance power measurements of the equipment as part of electromagnetic radiation. We propose a model which uses a mixed distribution for uncertainty evaluation. The evaluation of the probability density function for the measurand has been done using the Monte Carlo method and a modified least-squares method (combined method). For illustration, this paper presents mixed distributions of two normal distributions, normal and rectangular, respectively. [Projekat Ministarstva nauke Republike Srbije, br. III 43009 i br. 171007]

This paper deals with the analysis of correlation and regression between the parameters of particle ionizing radiation and the stability characteristics of the irradiated monocrystalline silicon film. Based on the presented theoretical model of correlation and linear regression between two random variables, numeric and real experiments were performed. In the numeric experiment, a simulation of the effect of alpha radiation on a thin layer of monocrystalline silicon was performed by observing a number of vacancies along the film depth resulting from a single incident alpha particle. In the real experiment, the irradiation of a thin silicon film by alpha particles from a radioactive Am-241 alpha emitter was performed. The observed values of radiation effect on the Si film were specific resistance and the concentration of free charge carriers. The results showed a fine concordance between numeric and real experiments. Correlation verification of the observed values was presented by linear regression functions. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

This paper investigates the possibility of distinguishing between the effects of radiation coming from two or more radioactive isotopes, by using methods of statistical mathematics. The procedure uses a mixed distribution of an additive type. Mathematical treatment is demonstrated herein on an example of analysis of composite radiation from two radioactive sources.

The Monte Carlo simulations of charged particle transport are used to investigate the effects of exposing ultra-thin layers of insulators (commonly used in integrated circuits) to beams of protons, alpha particles and heavy ions. Materials considered include silicon dioxide, aluminum nitride, alumina, and polycarbonate - lexan. The parameters that have been varied in simulations include the energy of incident charged particles and insulating layer thickness. Materials are compared according to both ionizing and non-ionizing effects produced by the passage of radiation. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

For the evaluation of measurement uncertainty in measuring the conduction emission, in this paper we propose a new model which uses mixed distribution. Evaluation of probability density function for the measurand has been done using Monte Carlo method and a modified least-squares method (combined method). In addition, the number of data n and the number of classes of histogram k which were used for simulation, were varied.

The paper investigates a possibility of pMOS dosimeter re-use for the measurement of gamma-ray irradiation. The dosimeters were irradiated to the dose of 35 Gy, annealed at room and elevated temperatures, after which they were irradiated again to the same dose value. Changes in the threshold voltage shift during those processes were followed, and it was shown that their re-use depends on a gate polarization during irradiation. For the gate polarization of 5 V during irradiation the pMOS dosimeters can be re-used for measurements of the irradiation dose after annealing without prior calibration. The pMOS dosimeters with the gate polarization during irradiation of 2.5 V can also be re-used for irradiation dose measurements but they require calibration. It is shown that for their re-use it is necessary to anneal the pMOS dosimeter so that the fading is higher than 50%. [Projekat Ministarstva nauke Republike Srbije, br. 171007]

Based on the principles derived from Campbell’s theorem, this paper carries out an analysis of the possibilities of Campbell’s mean square value signal processing system. The mean square value mode is especially suitable for measurements performed in a mixed radiation field, because the quantities of electrical charge involved in the interactions of the two types of radiation are substantially different. The measuring detector element may be an adequate ionization chamber and/or semiconductor components for mixed n-γ fields. An examination of the discrimination of gamma in relation to the neutron component in the signal of the detector output was carried out, calculated according to the theoretical model of radiation interaction with the detector. The advantage of the mean square value method was confirmed and it was concluded that the order of n-γ discrimination in mean square value signal processing is greater than the one rendered by the classical measuring method.

This paper investigates possible radiation effects in the Cooper-pair insulator state of indium oxide films. Radiation effects are predicted on the basis of Monte Carlo simulations. Results of a combined theoretical and numerical analysis suggest that radiation-induced changes in the investigated films could significantly affect their current-voltage characteristics, and that a transition to a metallic state is possible, due to radiation-induced disruption of the fine-tuned granular structure. Dissociation of Cooper pairs, caused by both the incident radiation and the ions displaced within InOx films, can also destroy the conditions for this specific insulating state to subsist.

Since the exact time a specific nucleus undergoes radioactive decay cannot be specified, nor can showers caused by secondary cosmic rays be predicted, statistical laws play an important role in almost all cases of experimental nuclear physics. This paper describes the method for the statistical treatment of nuclear counting results obtained experimentally by taking into account random variables pertaining to both frequent and infrequent phenomena. When processing counting measurement data, it is recommended to first discard spurious random variables that spoil the statistics by using Chauvenet’s criterion, as well as to test if the results in the statistical sample follow a unique statistical distribution by using the Wilcoxon rank-sum test (U-test). The verification of the suggested statistical method was performed on counting statistics obtained both from the radioactive source Cs-137 and background radiation, expected to follow the normal distribution and the Poisson distribution, respectively. Results show that the application of the proposed statistical method excludes random fluctuations of the radioactive source or of the background radiation from the total statistical sample, as well as possible inadequacies in the experimental set-up and show an extremely effective agreement of the theoretical distribution of random variables with the corresponding experimentally obtained random variables.

This paper investigates, through theory and experiment, the influence of the plain-parallel electrode surface dimensions change on the type A measurement uncertainty of a GM counter. The possibilities of applying these results to practical structures are examined by using the methods of mathematical statistics. Special attention is devoted to the influence of electrode surface enlargement on the statistical behavior of the pulse number random variable, expressed in the form of the enlargement law. In the theoretical part of the paper, the general surface enlargement law is derived. Comparison of experimental results with those predicted by the surface enlargement law proved its validity for expressing the type A measurement uncertainty of GM counters constructed with a plain-parallel electrode configuration with a homogenous electric field.

The effects of exposing titanium dioxide memristors to ion beams are investigated through Monte Carlo simulation of particle transport. A model assuming ohmic electronic conduction and linear ionic drift in the memristor is utilized. The memristor is composed of a double-layer titanium dioxide thin film between two platinum electrodes. Obtained results suggest that a significant generation of oxygen ion/oxygen vacancy pairs in the oxide is to be expected along ion tracks. These can influence the device’s operation by lowering the resistance of the stoichiometric oxide region and the mobility of the vacancies. Changes induced by ion irradiation affect the current-voltage characteristic and state retention ability of the memristor. If the displaced oxygen ions reach the platinum electrodes, they can form the O2 gas and cause a permanent disruption of memristor functionality.

GM counters are often used in radiation detection since they generate a strong signal which can be easily detected. The working principal of a GM counter is based on the interaction of ionizing radiation with the atoms and molecules of the gas present in the counter's tube. Free electrons created as a result of this interaction become initial electrons, i. e. start an avalanche process which is detected as a pulse of current. This current pulse is independent of the energy imparted on the gas, that being the main difference between a GM counter and the majority of other radiation detectors. In literature, the dependence on the incidence of radiation energy, tube's orientation and characteristics of the reading system are quoted as the main sources of measurement uncertainty of GM counters. The aim of this paper is to determine the dependence of measurement uncertainty of a GM counter on the volume of its counter's tube. The dependence of the pulse current on the size of the counter's tube has, therefore, been considered here, both in radial and parallel geometry. The initiation and expansion of the current pulse have been examined by means of elementary processes of electrical discharge such as the Markov processes, while the changes in the counter's tube volume were put to test by the space - time enlargement law. The random variable known as the 'current pulse in the counter's tube' (i. e. electrical breakdown of the electrode configuration) has also been taken into account and an appropriate theoretical distribution statistically determined. Thus obtained theoretical results were then compared to corresponding experimental results established in controlled laboratory conditions.

This paper compares the reliability of standard commercial Erasable Programmable Read Only Memory (EPROM) and Electrically Erasable Programmable Read Only Memory (E2PROM) components exposed to gamma rays. The results obtained for CMOS-based EPROM (NM27C010) and E2PROM (NM93CS46) components provide the evidence that EPROMs have greater radiation hardness than E2PROMs. Moreover, the changes in EPROMs are reversible, and after erasure and reprogramming all EPROM components restore their functionality. On the other hand, changes in E2PROMs are irreversible. The obtained results are analyzed and interpreted on the basis of gamma ray interaction with the CMOS structure.

The wide-spread use of semiconductor and gas-filled diodes for non-linear over-voltage protection results in a variety of possible working conditions. It is therefore essential to have a thorough insight into their reliability in exploitation environments which imply exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on over-voltage diode characteristics by exposing the diodes to californium-252 combined neutron/gamma radiation field. The irradiation of semiconductor over-voltage diodes causes severe degradation of their protection characteristics. On the other hand, gas-filled over-voltage diodes exhibit a temporal improvement of performance. The results are presented with the accompanying theoretical interpretations of the observed changes in over-voltage diode behaviour, based on the interaction of radiation with materials constituting the diodes.

This paper deals with possible ways of obtaining expanded and combined uncertainty in measurements for four types of GM counters with a same counter’s tube, in cases when the contributors of these uncertainties are cosmic background radiation and induced overvoltage phenomena. Nowadays, as a consequence of electromagnetic radiation, the latter phenomenon is especially marked in urban environments. Based on experimental results obtained, it has been established that the uncertainties of an influenced random variable ′number of pulses from background radiation′ and ′number of pulses induced by overvoltage′ depend on the technological solution of the counter’s reading system and contribute in different ways to the expanded and combined uncertainty in measurements of the applied types of GM counters.

The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.

This paper discusses the influence of radiation energy and angle of incidence as possible sources of uncertainties in measurements performed by GM counters. Based on the detection efficiency of GM counters, it has been concluded that the energy of incident radiation does not contribute to the overall uncertainty. The angle of incident radiation does contribute to overall uncertainty, but only in the case of gamma radiation detection. In that case, the uncertainty should be determined by using geometrical probability.