Improvement possibilities of the I-V characteristics of PIN photodiodes damaged by gamma irradiation

This paper presents the behavior of PIN photodiodes after combined gamma and neutron irradiation. Different types of PIN photodiodes have been exposed first to gamma and then to neutron irradiation. I-V characteristics (current dependence on voltage) of photodiodes have been measured after each of these irradiations. It has been noted that the photocurrent level after the neutron irradiation is higher than before it, which is not consistent with the current theories about the effects of neutron radiation on semiconductors. In order to explain this behavior of the photodiodes, the Monte Carlo simulation of photon transport through the material has been used. It is proposed that a possible cause for current enhancement are defects in semiconductor created by gamma irradiation and effects of neutron irradiation on these defects. The results can be explained by an intercentre transfer of charge between defects in close proximity to each other. The aim of this paper is to investigate the improvement possibilities of the I-V characteristics of PIN photodiodes, and photodetectors in general, damaged by gamma irradiation. [Projekat Ministarstva nauke Republike Srbije, br. 171007

Comprehensive comparison of in silico MS/MS fragmentation tools of the CASMI contest: database boosting is needed to achieve 93% accuracy.

In mass spectrometry-based untargeted metabolomics, rarely more than 30% of the compounds are identified. Without the true identity of these molecules it is impossible to draw conclusions about the biological mechanisms, pathway relationships and provenance of compounds. The only way at present to address this discrepancy is to use in silico fragmentation software to identify unknown compounds by comparing and ranking theoretical MS/MS fragmentations from target structures to experimental tandem mass spectra (MS/MS). We compared the performance of four publicly available in silico fragmentation algorithms (MetFragCL, CFM-ID, MAGMa+ and MS-FINDER) that participated in the 2016 CASMI challenge. We found that optimizing the use of metadata, weighting factors and the manner of combining different tools eventually defined the ultimate outcomes of each method. We comprehensively analysed how outcomes of different tools could be combined and reached a final success rate of 93% for the training data, and 87% for the challenge data, using a combination of MAGMa+, CFM-ID and compound importance information along with MS/MS matching. Matching MS/MS spectra against the MS/MS libraries without using any in silico tool yielded 60% correct hits, showing that the use of in silico methods is still important

Seroprevalence of serovars of pathogenic Leptospira in dogs and red foxes (Vulpes vulpes) from Bosnia and Herzegovina

The aim of this study was to examine the seroprevalence of Leptospira spp. in dogs and red foxes in the entity of the Republic of Srpska, Bosnia and Herzegovina, after heavy rainfall and floods in 2014 and for the two years thereafter. The seroepidemiological study involved testing serum samples from dogs (n = 98) and foxes (n = 112) using MAT (microscopic agglutination test). Antibodies to at least one Leptospira spp. serovar were found in 52.04% of the tested dogs. The dog seroprevalence in 2014 (81.25%) was significantly higher than in 2015 (51.42% p <0.0001) and 2016 (22.5% p<0.05). The highest seroprevalences were for serovars Australis (76.47%), Bratislava (70.58%), Sejroe (66.67%) and Autumnalis (45.09%). Antibodies to at least one Leptospira spp. serovar were detected in 34.82% of the examined red foxes. In 2015, the fox seroprevalence was significantly higher (52.94%) than in 2016 (6.82%) (p <0.0001). The highest seroprevalences were for serovars Sejroe (64.10%), Bratislava (48.72%), Australis (43.59%) and Bataviae (25.64%). The high seroprevalence of Leptospira spp. in dogs and foxes determined during this study indicates the importance of these carnivores in maintaining leptospirosis in the study area, and the potential risk of infection for humans and other animal species that come into contact with these canids. The results obtained indicate that heavy rainfall and intense floods can result in increased Leptospira spp. infection in these canids

Comparison of the Empirical Variances and Mean Values of Normally Distributed Populations of Nuclear Counts

This paper discusses the possibility of applying the F-test and double t-test in problems related to the identification of number of radioactive isotopes in a contaminated area by using only counters for radiation detection. The descriptions of the F-test and the double t-test are given along with the corresponding tabular values that enable their implementation. Finally, the experiment is presented via two radioactive samples. The results of the experiment were treated in the manner proposed in the paper and satisfactory results were obtained

NAJVAŽNIJE BOLESTI PASA I MA9AKA I NOVI TRENDOVI U IMUNOPROFILAKSI

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Statistical review of the insulation capacity of the geiger-mueller counter

This work considers the manifestation of spontaneous breakdowns of Geiger-Mueller counters. This is an experimental type of work. The reasons leading to the spontaneous breakdowns of Geiger-Mueller counters have been analysed under controlled laboratory conditions. The experiments were carried out under the "constant voltage". The tested Geiger-Mueller chambers were commercial chambers of the radial electric field and homogenous electric field. The experimental-statistical methods were used in order to choose the chambers with identical features (with 0.1 % of statistical reliability).The results of experiments showed that the spontaneous breakdown of the Geiger-Mueller counter happens even in the conditions of shielding. They also showed that those breakdowns have cumulative features. The reason for that is a positive feedback between the spontaneous breakdowns. The explanation is confirmed and quantified by the working gas filtering experiments

Numerical Simulations of Pulsed Power Electronic Components Radiation Hardness

An increasing degree of both semiconductor components miniaturization and electromagnetic contamination of the environment brings into question the reliability of modern electronic devices. This is particularly emphasized in the functioning conditions of electronic devices related to: nuclear power facilities, medical devices based on nuclear particle and x-ray radiation and the impulse power device. At the same time, non-resistance of semiconductor components to the effects of particle and electromagnetic radiation represents the basic limitation of the expected development of nanoelectronic components. Since the most commonly used material for manufacturing semiconductor components is monocrystalline silicon, it is of great significance to be aware of the influence of nuclear particle and electromagnetic radiation on its relevant. Based on the well-known effects of nuclear (particle) interactions and electromagnetic radiation, the biggest influence on the electrical characteristics of monocrystalline silicon should be expected from neutron (n), x-ray (x) and gamma (gamma) radiation. The evaluation of such influence is often carried out (for economic and security reasons) by simulating the effect of radiation interaction with the material, applying the Monte Carlo method (numerical experiments). The aim of this paper is to evaluate the application of the Monte Carlo method for this class of problems. For this purpose, the effect of n, x and gamma radiation on the electrical characteristics of monocrystalline silicon will be determined, under the well-controlled laboratory conditions. The parameters of the experiment are energy and radiation dose. Electric characteristics of monocrystalline silicon are determined using the four-point method and the thermal method. The corresponding numerical experiments will be conducted simultaneously with these laboratory experiments. On the basis of already obtained statistical samples (laboratory and numerical experiments), the testing of both correlation and regression between them will be carried out. The results will provide an answer to the question concerning the feasibility of the Monte Carlo method for the described class of problems2015 IEEE Pulsed Power Conference (PPC), Proceedings, May 31-Jun 04, 2015, Austin, T