The problem of finding an exact analytical closed form solution to the degree of the nuclear fuel burn-up simple transcendental equation is studied in some detail, by using the Special trans functions theory (STFT). Structure of the STFT solutions, derivations, numerical results and graphical simulations confirm the validity and base principle of the STFT

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The charge collection performance of a diamond-graphite detector is reported. Buried graphite pillars with high aspect ratio were formed inside a single crystal synthetic diamond slab by using a femtosecond IR laser with 200 kHz of repetition rate. Grouped in two series and connected by graphite strips on the surface, eight independent 3D electrodes were used to collect the charge carriers generated by energy deposited in the detector. Collimated ⁹⁰Sr,Y -particles were used to test the charge collection in coincidence and self-triggering mode among pillars rows using different irradiation geometries. The charge collected by one pillar row saturates at 1.40±0.02 fC at ±0.67V/m with electrons impinging orthogonally the rows demonstrating a high charge carrier collection efficiency.

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Silicon carbide (SiC) and nitrogen-doped silicon carbide (SiC(N)) films were deposited on p-type Si(100) substrates at various deposition conditions by means of plasma enhanced chemical vapor deposition (PECVD) technology using silane (SiH₄) methane (CH₄) and ammonium (NH₃) gas precursors. The concentration of elements in films was determined by RBS and ERD analytical method simultaneously. Chemical compositions were analyzed by FT-IR and Raman spectroscopy. The current-voltage (I-V) characteristics of structures before and after Xe ion and neutron irradiation were measured.

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The research is focused on the differences in radiation behavior for transistors of different geometry, body tie contact types, device layer thickness and biasing.

1. A.V. Sogoyan, A.I. Chumakov and A.Y. Nikiforov, “Method for Predicting CMOS Parameter Degradation Due to Ionizing Radiation with Regard to Operating Time and Conditions,” Russ. Microel., vol. 28, no. 4, pp. 224-235, 1999.
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In this paper the results of modeling and simulation of radiation stress effects in p-channel power VDMOSFET transistor have been presented. Based on measured results, the threshold voltage shifts as a function of absorbed dose and gate voltage during radiation stress have been modeled and implemented in the PSPICE model of the IRF9520 transistor. The transfer characteristics of the transistor are simulated and compared to the experimental ones. Difference is in the range 0.16% to 23.35% which represents a good agreement.

1. Y. Deng, T. Ytterdal, T. Fjeldly and M. Shut, “SPICE Modeling of Double Diffused Vertical Power MOSFETs Exposed to Gamma Radiation,” Semicond. Dev. Res. Symp., Washington DC, USA, 2003, pp. 138-139.
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Parapositronium – a singlet positronium ground state, has the total angular momentum of electron and positron forming the atom J_s = 0, magnetic quantum moment m = 0, and its annihilation spectrum is dominantly created by the 511 keV discrete photons. A process of cooperative emission of annihilation photons (cooperative annihilation) by a system of positronium atoms, i.e., annihilation superradiance, had been considered by other researchers, and the theory of annihilation superradiance in a system of parapositronium atoms for two-photon annihilation was constructed (two interacting parapositronium atoms; emission of the 1022 keV photons flying apart at an angle of 180°). The 32-crystal spectrometer ARGUS, with 16 detector pairs at an angle of 180° capable of registering double gamma coincidences, with lead collimators (80 mm in diameter) mounted on each detector – was used to test the phenomenon. Parapositronium annihilation spectra were acquired using ²²Na (A = 4×10⁵ Bq) as a positron source, and SiO₂ (as „positronium forming“ medium; probability: 32 %), as well as Al (as „positronium not forming“ target) used as a blank – for estimation of the background events. In the case when after emission of two starting positrons from ²²Na (i.e., the 1275 keV nuclear photons) coincident registration (respecting the spectrometer time resolution) of four annihilation photons should be considered as a six-fold coincidence event, experimentally obtained counting rates were – 0.25 s^-1 (SiO₂) and 0.23 s^-1 (Al), while theoretically predicted – 0.34 s^-1. The main background process competitive to a registration of the parapositronium cooperative annihilation is four-fold coincidence event (the two 180° detectors register 1275 keV photons, and two – summing of the 511 keV annihilation photons), with experimental counting rates – 0.026 s^-1 (SiO₂) and 0.023 s^-1 (Al), as theoretically predicted – 0.023 s^-1. On the other hand, cooperative annihilation should be a four-fold coincidence event (the two 180° detectors register 1275 keV photons, and two – 1022 keV photons), which has not been registered by the ARGUS spectrometer (theoretically predicted counting rate – 1.7×10^-5 s^-1). The analyses showed that probability of detecting the parapositronium cooperative annihilation will increase significantly with increasing positron source activity, but also with decreasing diameter of lead collimators.

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The results of an intercomparison exercise, designed for the determination of anthropogenic and natural radionuclides in sediment and fish samples from the Danube River, are reported. The methods of gross beta and gamma spectrometry measurements were compared. Considering the uncertainties of measurements, a good agreement between the results obtained by two laboratories has been ascertained.

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3. J.D. Krneta Nikolic, D.J. Todorovic, M.M. Jankovic, G.K. Pantelic and M.M. Rajacic, “Quality Assurance and Quality Control in Environmental Radioactivity Monitoring,” Q. A. Safety Crops & Foods, vol. 6, no. 4,pp. 403-409, 2014.
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The Personal Radiation Detector (PRD) γ-Tracer GT2-1 was developed with a focus on gamma-radiation searches and detection and offers a gamma-radiation source localization function, enhanced PRD features and the capability of isotope energy pattern analysis. The device complies with general requirements and includes all typical features of PRD-class devices as well as supplementary modes such as multi-channel scaling (MCS), a spectrometer, library-driven analysis and a data logger. The GT2-1 uses a detector module built around a 0.4 cm³ counting-grade planar CdZnTe detector. CdZnTe offers high-efficiency gamma-radiation detection for a small detector volume and energy discrimination down to 30 keV. The GT2-1 was designed with power consumption in mind; its typical lifetime after a full battery charge exceeds 600 hours in measurements mode. Energy compensation techniques are employed for the dose rate calculations. The typical accuracy of the device in the energy range of 30–1500 keV is better than 10% for factory-calibrated devices. The GT2-1 features a library-driven isotope identification function. Its underlying concept is the use of a library of pre-calibrated user-defined isotope patterns for comparison with the isotope under investigation. The identification algorithm is designed to evaluate the isotope energy pattern match. The execution of the algorithm yields the matching results between the tested isotope and the library in graphical form. The device’s search mode employs a proprietary Background Variation Tracking (BVT) algorithm. The implemented search and gamma-radiation source localization mechanisms facilitate the rapid (1–3 sec) detection of weak gamma-radiation sources with intensities that exceed the background level by a factor of 1.5–3. Analysis of the time intervals between adjacent pulses in the input sequence is used to determine numeric characteristics that are also displayed in a user-friendly graphical form. The dedicated GUI approach and sound capabilities are tailored to facilitate search activities and support the operator in gaining experience with the device. The dedicated search algorithm implementation allows the device to be used as a homeland security detector by services responsible for the control of the relocation of radioactive materials, such as those at airports, border control checkpoints, and tolls. Test results for the GT2-1 in search mode are presented.

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In cancer research the radiation dose delivered to different organs presents a critical parameter for destroying the cancer cells’ DNA, but the biochemical pathways that bring cells to death in many cases start at the cell membrane whose major part consists of lipid molecules. In our XPS and NEXAFS experiment, we exposed a monolayer lipid film supported on gold to a spatially and energetically well defined electron beam (20 eV), simulating the charged particle avalanche produced in the exposure of the biological tissue to a high-energy ionizing radiation (X- and g - rays, ions, etc). Oxygen and nitrogen 1s edge scans show a clear chemical degradation of the DPPC monolayer. The major damage has been inflicted to the polar head of the molecule and its links with the molecules’ alkane chains.

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9. N.T. Samuel, C.Y. Lee, L.J. Gamble, D.A. Fischer and D.G. Castner, “NEXAFS Characterization of DNA Com-ponents and Molecular-Orientation of Surface-Bound DNA Oligomers,” J. Elect. Spec. Rel. Phen., vol. 152, no. 3, pp. 134-142, July 2006.
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11. E. Novakova, G. Mitrea, C. Peth, J. Thieme, K. Mann, and T. Salditt, “Solid Supported Multicomponent Lipid Membranes Studied by X-Ray Spectromicroscopy,” Biointerph., vol. 3, no. 2, pp. FB44-FB54, June 2008.
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12. LIPID Metabolites and Pathways Strategy “Lipid MAPS”, Data bases. Retrieved from: http://www.lipidmaps .org/resources/services.html.
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14. R. Panajotovic, F. Martin, P. Cloutier, D. Hunting and L. Sanche, “Effective Cross Sections for Production of Single-Strand Breaks in Plasmid DNA by 0.1 to 4.7 eV Electrons,” Rad. Res., vol. 165, no. 4, pp. 452-459, Apr. 2006.
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In the present work, the phenomenon of bystander effects (transfer of damaging factors from affected cells to intact cells) induced in vivo has been studied. A newly developed method allows evaluation of the effects of bystander factors from sera of different groups of populations on immortalized culture of human keratinocytes. This method has serious advantages as compared to that which was used earlier. The level of damaging bystander factors in blood of people irradiated by the Chernobyl accident was estimated. Affected population groups included liquidators of the Chernobyl accident and people living and working in areas of Gomel region contaminated by radionuclides. The data clearly shows that blood serum samples of irradiated populations contain some kind of factors, induced in vivo and able to cause cell damage when transferred to in vitro conditions. These factors are able to circulate in blood stream for more than 20 years.

1. H. Nagasawa and J.B. Little, “Induction of Sister Chromatid Exchanges by Extremely Low Doses of Alpha-Particles,” Cancer Res., vol. 52, no. 22, pp.6394-6396, Nov. 1992.
2. B.E. Lehnert and E.H. Goodwin, “A New Mechanism For DNA Alterations Induced by Alpha Particles Such as Those Emitted by Radon and Radon Progeny,” Envir. Health Persp., vol.105, suppl. 5, pp.1095–1101, Sep. 1997.
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3. E.I. Azzam, S.M. de Toledo, T. Gooding and J.B. Little, “Intercellular Communication is Involved in the Bystander Regulation of Gene Expression in Human Cells Exposed to Very Low Fluencies of Alpha Particles,” Rad. Res., vol.150, no. 5, pp.497–504, Nov. 1998.
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4. A. Bishayee, D.V. Rao and R.W. Howell, “Evidence for Pronounced Bystander Effects Caused by Nonuniform Distributions of Radioactivity Using a Novel Three-Dimensional Tissue Culture Model,” Rad. Res., vol.152, no.51, pp.88-97, July 1999.
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Fluoroscopy procedures may lead to increased radiation exposure of radiologists and other staff members. The objective of the study is to assess whole body radiation doses and doses to the eye in fluoroscopy procedures, based on measurements that allow for estimates of occupational doses when personal dosimeters have not been used. Four geometrical configurations were considered: overcouch x-ray tube with and without table mounted lead rubber curtains in place, undercouch x-ray tube with horizontal x-ray beam and undercouch x-ray tube with vertical x-ray beam. The doses were estimated using distribution of the scattered radiation and typical workload, as well as the pattern of used of protective tools. Estimated effective dose was in the range from few to 60 µSv per procedure for radiologist, and from few to 20 µSv per procedure for radiographer, depending on the geometrical configuration and level of personal protection. Corresponding unprotected eye doses were estimated to be in the range 0.03 – 2.8 mSv per procedure for radiologist and 0.02-0.78 mSv for radiographer. The presented results allowed for realistic estimations of the occupational whole body dose and dose to the eyes from the workload of the staff members and from the level of use of radiation protection tools when personal dosimeters have not been regularly used.

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The paper presents a summary of the main steps in carrying out the refurbishment of the research reactor IRT in Sofia. It was a 2 MW pool type light water cooled and moderated reactor which after the final shutdown was defueled and brought to a state of safe enclosure. According to a decision of the Bulgarian Government it undergoes a reconstruction into a low-power reactor. In this regard during the period 2008 - 2014 within the IRT-Sofia took place a number of activities with potential for radiation hazard such as shipping of the spent nuclear fuel, dismantling of the reactor internals and replacement of aged reactor equipment, categorization, sorting and packaging for temporary storage of dismantled equipment and the radioactive waste generated during the dismantling activities. The report gives information on the organization and management of the activities and outlines some key technical aspects of the dismantling and removal of the contaminated/activated components. Also, the experience gained during this project is highlighted, particularly with a view to methods for the separation of radioactive waste from material to be cleared. The radiation measurements and site monitoring prior, for the period of all the activities and at present supplied comprehensive evidence that the work has been accomplished safely for the personnel and without radiation consequences for environment.

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The paper summarizes some basic issues related to the protection of people against the danger resulting from a radiological weapon or the so-called dirty bomb which can potentially be used in terrorist or other malevolent attacks. The properties of radioactive material utilized for this purpose and the quantification of the exposure of affected persons, the prevention measures against and consequences of radiological acts as well as appropriate arrangements aimed at minimizing their impacts are described. In addition, an overview of global initiatives addressing the fight against terrorism in general, including CBRN terrorism, is also presented.

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adon concentration measurements were performed in indoor air and in natural mineral waters in seventeen Portuguese thermal spas used for therapy, drinking and irrigation purposes. The gamma doses rates were also assessed in different workplaces of the considered thermal spas. The radon concentration was measured in water samples taken from different sampling points: boreholes, springs, inhalator chambers (ORL’s) and swimming pools, and in the indoor air of different treatment rooms: ORL’s, swimming pools, vapours areas and Vichy shower. Radon concentration in water ranged from 26 to 6949 Bq/L and in the indoor air ranged from 73 Bq/m3 to 3479 Bq/m3. The indoor gamma dose rates ranged from 0,148 µSv/h to 0,644 µSv/h and the annual dose rate was estimated ranging from 0,30 to 1,29 mSv/y, for 2000 working hours per year, which is far below the effective dose limit for workers (20 mSv/y). Nevertheless, the great contribution for the annual effective dose will result from radon inhalation which is not included in this estimation. The remedial action level for drinking water of 1000 Bq/L (2001/928/ EURATOM) was exceeded in 23% of the selected thermal spas and about 80% of the total measurements of the indoor radon concentration exceeded the previous reference level of 200 Bq/m3 for new buildings and about 63% exceeded the new reference level of 300 Bq/m3 as established in the Directive 2013/59/EURATOM for indoor radon concentration in workplaces. Therefore, as the recommended limits for radon concentration in water and in indoor air were exceeded, appropriate actions should be taken in order to reduce the hazard to health from radon indoors and the potential resulting occupational exposure.

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The possible influence of errors of radon exposure assessment on the results of planned national case-control study has been analyzed. It is demonstrated that, in general, the errors are classical multiplicative errors. It is demonstrated that the classical multiplicative errors of radon concentration measurement are not constant in all radon concentration ranges. At low radon concentrations, the additional influence of Poisson error on the measurement result should be considered. The modeling of the influence of errors of radon exposure assessment on slope factor of the dependence of lung cancer incidence on radon concentration in dwellings was conducted. It was shown that the expected level of radon exposure errors can reduce the observed value of slope coefficient at least twice in comparison with the original value for error-free study. The correction of the results of linear assessment of exposure-effect slope coefficient under the influence of measurement errors was realized by regression calibration technique and SIMEX extrapolation method. Regression calibration method gives the best results in restoring the original unbiased value of exposure-effect slope coefficient. The SIMEX method also allows the obtainment of the good assessment of expected value of the slope of exposure-effect dependence, but it should be noted that this method may lead to the underestimation of the real value of slope coefficient. An additional and the most powerful source of error in the radon epidemiological studies is the influence of smoking and the correlation between smoking status and radon concentration in dwellings. The modeling results demonstrated that maximum attention should be paid to the stratification by smoking status and other possible factors simultaneously influencing radon concentration in dwellings and lung cancer incidence.

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