Search

The effectiveness of ionizing radiations for the preservation of cultural heritage (CH) has been recently demonstrated. Although these processes present many advantages with respect to the traditional methods, physico-chemical modifications induced by radiation (namely side effects) represent a concern for CH restorers, archivists and librarians. The present work is focused on the study of the effect of gamma irradiation parameters on the main features of paper. In particular, total absorbed doses up to 10 kGy (commonly suggested for preservation treatments) have been applied, with dose rates ranging from 3 to 10 kGy/h. Different experimental techniques (FTIR, EPR, viscosity and colorimetric analysis) have been used to study the side effects occurrence. The results indicate that the fine-tuning of irradiation condition allow to minimize the unwanted changes, induced by radiation in the treated paper samples. • Gamma radiation at absorbed doses common for preservation of cultural heritage (up to 10 kGy). • Side effects evaluation with several experimental techniques (FTIR, EPR, DP, colorimetric analysis). • Studies were performed at different dose rate values. • Irradiation parameters optimization to minimize the side effects. • Gamma rays represent a suitable and reliable tool for bio-deteriogens elimination purpose. [ABSTRACT FROM AUTHOR]

• Alternative procedure for components TID radiation qualification. • Comparative analysis between gamma rays versus X-rays as TID radiation source. • Medical LINAC valid for a TID characterization as a radiation source of electronic components. Ionizing radiation can cause temporary or permanent failures in electronic components used in space applications. The characterization of these components and the design of on-board electronic systems that are tolerant and functional under these conditions are fundamental requirements in flight systems engineering. This paper presents experimental results from tests performed with 60 Co as gamma radiation source, comparing them with those results obtained with a medical LINAC (LINear ACcelerator) producing X-rays with similar energy. Following ESA ESCC-22900 standard it was shown that the results achieved with both radiations are equivalent, and therefore we prove that medical LINACs, that are much more easily accessible than 60 Co facilities, are suitable for testing electronic systems for space applications. [ABSTRACT FROM AUTHOR]

The hydrogen production during radiation-thermal processes of water and stainless steel systems at different temperatures was studied. As a result of the energy transfer of ionizing radiation and the interaction of active intermediates with the initial components, the formation of molecular hydrogen occurred. With an augment in temperature from 300 to 673 K, an increase in hydrogen yield was reported. It has been established that at a temperature of 673 K, a chain mode of transformation of the primary products of stainless steel radiolysis into molecular hydrogen was obtained. The values of G(H 2) were 2.50, 3.95, 5.0, 7.11 and 10.5 at 300, 373, 473, 573 and 673 K temperature. On the other hand, these values were 5.11, 9.15, 11.0, 12.5, 16.5 and 25.5 molecules/100eV at 80, 160, 240, 320, 400 and 480 Gy, respectively. At 473 K, an oxidative layer was formed on the surface of stainless steel, while at 523 K, insoluble surface oxidizing products were formed. The main radiation corrosion was observed at T ≥ 573K. At 300–673K temperature ranges, the corrosion rate of stainless steel increased by 4–5 times during radiation-heterogeneous procedures. As a result of these processes, an oxide film was formed on the surface, which prevented further oxidation of the metal. This work is important for hydrogen production and stainless steel corrosion. This paper will be highly useful for hydrogen production and the use of stainless steel in nuclear reactors. • Inexpensive hydrogen production from water radiolysis with stainless steel catalyst. • Optimization of radiolysis to achieve maximum hydrogen. • Oxide formed on steel preventing further oxidation; useful in nuclear reactors. • First time molecular hydrogen calculation based on radiation dose. • Work is useful for hydrogen production and nuclear reactors. [ABSTRACT FROM AUTHOR]

Microbiological analysis of wheat (Triticum aestivum L.) treated with different doses of ionizing radiation (0.2 kGy, 0.5 kGy, 1 kGy, 5 kGy and 10 kGy) is presented in this paper. The aim was to determine the influence of different irradiation doses on the microbial population profile of wheat. In all samples, the total bacterial count and the populations of Enterobacteriaceae , Escherichia coli , Salmonella spp , coagulase-positive Staphylococci , Pseudomonas aeruginosa , Bacillus cereus , Clostridium perfringens , yeasts and molds were examined. The analyses were carried out twice: immediately after irradiation and nine months after treatment. Obtained results revealed the presence of Bacillus cereus , Enterobacteriaceae , yeasts and molds in all examined samples. Salmonella spp , Pseudomonas aeruginosa , Escherichia coli and Clostridium perfringens , were not detected. It has been found that the number of microorganisms decreases with the increase in the irradiation dose, with no viable microorganisms detected at the dose of 10 kGy. In all examined samples, nine months after irradiation, there was a noticeable reduction in the number of microorganisms. Only yeasts and molds were detected at a dose of 5 kGy, while no microbial growth was observed at 10 kGy. There are no reference studies on Enterobacteriaceae inactivation in wheat by ionizing radiation and storage. Therefore this study is the first contribution to understanding this microbial community decrease by gamma radiation after room temperature storage. The results highlighted the prolonged effect of ionizing radiation treatment on the microbiological safety of wheat. • The microbiota of wheat (Triticum aestivum L.) consists of Bacillus cereus, Enterobacteriaceae, yeasts and molds. • The detected microbial populations followed an inactivation by gamma radiation in a dose-dependent manner. • The inactivation of the Enterobacteriaceae population growth in wheat samples was verified only at 5 kGy. • Inactivation of microbial growth after irradiation and storage period was achieved at 10 kGy. [ABSTRACT FROM AUTHOR]

Ionizing radiations are a unique and powerful means of modifying physico-mechanical properties of various polymers and composites. Modification of properties by irradiation technique has become a pioneer area of research due to its extraordinary results and toxic-free route. Many studies revealed that radiations act differently on polymers and composites. At the optimal radiation dose; various mechanical properties such as tensile, compression, impact and flexural strength/modulus were improved upto some extent. This paper gives a clear overview of different types of radiations used for altering the properties of polymers and its composites reinforced with natural and synthetic fillers. Furthermore, the current area of research has been documented in this review. In nutshell, high-energy gamma rays and electron beam act a promising technology and bettter alternative of traditionally used chemical methods to modify various chemical and physico-mechanical aspects of commerical available polymers and composites. [ABSTRACT FROM AUTHOR]

The treatment of dye-containing wastewater generated from textile industries is still a challenge, and various technologies, including physical, chemical and biological ones have been used. In recent years, the ionizing radiation (usually including gamma ray generated by radionuclide, such as 60Co and 137Cs, and electron beam generated by electron accelerator) technology has received increasing attention for degrading refractory or toxic organic pollutants in wastewater because of its unique advantages, such as no chemical additives, fast reaction rate, strong degradation capacity, high efficiency, flexibility, controllability. Compared to the conventional wastewater treatment processes, ionizing radiation technology, as a disruptive wastewater treatment technology, is more efficient for the decolorization and degradation of dyes and the treatment of dye-containing wastewater. In this paper, the recent advances in the treatment of dye-containing wastewater by ionizing radiation, in particular by electron beam (EB) radiation were summarized and analyzed, focusing on the decolorization and degradation of various dyes. Firstly, the formation of various reactive species induced by radiation and their interactions with dye molecules, as well as the influencing factors on the removal efficiency of dyes were discussed. Secondly, the researches on the treating dye-containing wastewater by electron beam radiation technology were systematically reviewed. Then, the decolorization and degradation mechanisms by electron beam radiation were further discussed in detail. And the integrated processes that would contribute to the advancement of this technology in practical applications were examined. More importantly, the recent advances of electron beam radiation technology from laboratory to application were reviewed, especially successful operation of dye-containing wastewater treatment facilities in China. And eventually, current challenges, future research directions, and outlooks of electron beam radiation technology were proposed for further advancing this technology for the sustainable development of water resources. [Display omitted] • The treatment of dye-containing wastewater is still a challenge. • Advances in dye-containing wastewater treatment by EB were summarized and analyzed. • Mechanisms of dye decolorization and degradation by EB were discussed in detail. • EB is more efficient for the decolorization and degradation of dyes. • Challenges, future directions and outlooks of EB technology were proposed. [ABSTRACT FROM AUTHOR]

The utilization of ionizing radiation, such as gamma ray and electron beam, in medical product sterilization has seen significant growth in recent years, driven by concerns regarding the safety of ethylene oxide sterilization. This paper examines the effects of these radiation modalities on silicone rubber, and its applicability on a silicone rubber-containing medical device, specifically a silicone foley catheter, by assessing its functional properties before and after irradiation at varying absorbed doses. Analysis of the irradiated samples revealed the presence of carbonyl groups, indicating radiation-induced oxidation. Gamma irradiation did not exhibit fundamental changes in the polymer structure but showed degradation at higher temperatures due to oxidation mechanisms. Moreover, a significant decrease in elongation at break was observed indicating that the already highly crosslinked silicone rubber experienced additional crosslinking affecting its mechanical properties. In contrast, both irradiations led to degradation, as evidenced by a decrease in TG residue. However, the mechanical properties, including tensile strength and elongation at break, were less affected. This suggests limited crosslinking and fragmentation of the polymer backbone. At a lower dose, a decrease in both strength and elongation indicated the formation of branched structures, limiting mobility, introducing irregularities, and weakening the polymer's overall strength. Despite these effects, the functional properties of the silicone foley catheter were practically unaffected at low absorbed doses, except for the discoloration of the syringe ports. Overall, the study provides insights into the effects of ionizing radiation on silicone rubber, highlighting the complex interplay between crosslinking, chain scission, and oxidation mechanisms. The findings contribute to understanding the changes in the polymer's structure and properties under different radiation modalities and doses, facilitating the development of effective sterilization techniques for medical devices containing silicone rubber. • Irradiation induced carbonyl groups in silicone rubber, observed across different catheter polymers. • Gel fraction and swelling ratio stable, but thermal profile indicated side-chain degradation. • %Elongation at break reduced due to increased polymer backbone crosslinking, making it rigid. • Potential sterilization doses: 15 kGy gamma ray or 15–35 kGy electron beam. [ABSTRACT FROM AUTHOR]

The surfaces of the works of art are one of their most important parts since they interact directly with the observer's perception. On the other hand, they are also in direct contact with physical, chemical and biological agents that can induce degradation and signs of aging. Dust deposits, stains and aged layers of protection can degrade, causing irreversible damage to works of art. In this way, the removal of undesirable materials from artistic surfaces is essential to preserve cultural heritage articles. The aim of this work was to develop silver nanoparticles-based hydrogels and to study the behavior regarding solvent concentration, stability and ability to clean dirt samples based on paper and canvas. The hydrogels were synthesized (reticulated) by gamma rays having the simultaneous formation of silver nanoparticles (AgNP) in the same process. The samples were characterized by swelling tests, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and optical microscopy (OM). The results showed the removal of dirt from the paper samples, as well as the softening of the dirt from the canvas, without leaving residues and without affecting the integrity of the art works submitted to treatment. • The hydrogel is capable of removing dirt from paper and fabric. • Cleaning with hydrogels does not affect the integrity of cultural heritage. • Crosslinking, non-reducing silver reduction and sterilization by gamma radiation. [ABSTRACT FROM AUTHOR]

This paper presents the synergistic effects in bipolar operational amplifier OP07. The radiation effects are studied by neutron beam, gamma ray, and mixed neutron/gamma ray environments. The characterateristics of the synergistic effects are studied through comparison of different experiment results. The results show that the bipolar operational amplifier OP07 exhibited significant synergistic effects in the mixed neutron and gamma irradiation. The bipolar transistor is identified as the most radiation sensitive unit of the operational amplifier. In this paper, a series of simulations are performed on bipolar transistors in different radiation environments. In the theoretical simulation, the geometric model and calculations based on the Medici toolkit are built to study the radiation effects in bipolar components. The effect of mixed neutron and gamma irradiation is simulated based on the understanding of the underlying mechanisms of radiation effects in bipolar transistors. The simulated results agree well with the experimental data. The results of the experiments and simulation indicate that the radiation effects in the bipolar devices subjected to mixed neutron and gamma environments is not a simple combination of total ionizing dose (TID) effects and displacement damage. The data suggests that the TID effect could enhance the displacement damage. The synergistic effect should not be neglected in complex radiation environments. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the effect of very low dose gamma radiation exposure on the plasmonic behavior of gold nanoparticles. For this purpose, gold nanoparticles were exposed to three different dose rates of radiation, with the absorbed doses of 0.33, 0.56 and 0.75 milligray. Subsequently, the effect of radiation exposure on the color of the solution, which is due to the accumulation of nanoparticles in the presence of salt, was investigated using visible spectroscopy. The results show that the presence of radiation can change the behavior of gold nanoparticles in the presence of salt for a specified period, in a way that the spectrum is similar to the spectrum of nanoparticles in the absence of salt. Based on these observations, a simple way of detecting ionizing radiation is introduced. • Gold nanoparticle irradiated with gamma ray. • Response of sample to salt was investigated with visible spectroscopy. • Simple radiation detection based on plasmonic behavior was purposed. [ABSTRACT FROM AUTHOR]

In this review, we have recalled the main test stages carried out, aimed at receiving the authorization for ionizing radiation treatment for deteriorated books and archive documents, as a physical means for their recovery from the most important biodeteriorating agents. The first radiobiological tests were carried out on the efficiency of the treatment against insects and micro-organisms; after, we carried out other tests to identify any damage caused by radiation to the constitutive material of books (i.e. cellulose and paper) and to the printing inks that could endanger the mechanical and physical properties of this material during the following conservation period, or even to facilitate the attack of the harmful deteriorating agents or strengthen their harmfulness. The whole field evidence leads to state that gamma radiation treatment, if carried out using the correct doses needed for the recovery of the material, does not cause any contra-indication for the material itself. A responsible cost–benefit analysis of the action indicates that the use of this treatment is a valuable option compared to the chemical substances used so far, which have proven to be toxic and harmful for men and environment.Research aims: The present work [describes and] summarizes the experimental research performed by the author on the effects of gamma radiation on organisms that damage books: insects and microscopic fungi (molds). Paying particular attention to the depolymerization of cellulose, the author investigated whether and to what extent this undesirable collateral effect of irradiation on the principal structural component of books represents a real obstacle to the introduction of a promising technology for sanitizing of infested material. [Copyright &y& Elsevier]

Using ionizing radiation in treating waste sludge from a drinking water treatment plant is a well-known technique. Sludge treated with ionizing radiation can be used as fertilizer in agriculture. In this paper, the effects of aging on the physicochemical characteristics, the content of microorganisms, molds, acrylamide, heavy metal concentration, and total nutrient content in waste sludge treated with e-beam and gamma irradiation were investigated. The possibility of using treated sludge as a fertilizer in agriculture was evaluated. It has been shown that the content of acrylamide in treated sludge after 15 months of storage does not exceed the limits for sludge to be used as fertilizer. If the sludge is stored in closed bags in a dark place, aging does not increase total microorganisms and molds. The research also showed that the sludge's physicochemical characteristics treated in this way do not decrease under the influence of aging. Finally, it has been shown that aging does not change the concentration of heavy metals and total nutrients in sludge treated by ionizing irradiation. • Effect of gamma and e-beam radiation on removal of pathogens from sludge was shown. • The effects of aging on the physicochemical characteristics were investigated. • Content of heavy metals and total nutrient content in sludge was measured. • The concentration of acrylamide in sludge was determined. • This sludge complies with the Directives and can be used as fertilizer in agriculture. [ABSTRACT FROM AUTHOR]

Four sulfide compounds' attenuation features of gamma-ray (Ag 2 ZnSnS 4 , Ag 2 ZnSnSe 4 , ZnS, and Ag 2 S) were described in this paper by a new software Phy-X/PSD. We calculated radiation attenuation parameters for the selected samples for a broad range of energies (0.015–15 MeV), including linear attenuation, the mean free path, the half-value layer, and total atomic and electronic cross-sections. The effective atomic number and the effective conductivity were also analyzed to investigate the radiation attenuation features. Also, the analyzed samples' buildup factors were studied. The samples' parameters were compared to materials frequently used to shield against radiation, including ferrite, chromite, barite, magnetite, and RS (253 G18, 360, 520) glass. Due to MFP and HVL values, Ag 2 S has better attenuation features than all the other samples utilized in the comparison. Fast neutron removal cross-sections (FNRCS) were also studied, and the best neutron attenuation composite among the samples under study, according to the FNRCS data, is Ag 2 S (0.116 cm−1). [ABSTRACT FROM AUTHOR]

Recently, water treatment by ionizing radiation has gained increasing attention as a powerful technology for the destruction of refractory pollutants. 2-Mercaptobenzothiazole (MBT) is known as a widespread, toxic and poorly biodegradable pollutant. This paper studied the gamma irradiation of aqueous solutions of MBT. Moreover, the effect of the addition of persulfate (S 2 O 8 2 − ) on the radiolytic destruction of MBT was investigated. The main transformation products of the studied compound were detected and the sequence of occurrence of the products was described. The change of biodegradability of MBT solution was also observed. The main results obtained in this study indicated that gamma radiation was effective for removing MBT in aqueous solution. Persulfate addition, which induced the formation of reactive sulfate radicals (SO 4 − ), greatly enhanced the degradation of MBT. Benzothiazole was identified as the first radiation product, followed by 2-hydroxybenzothiazole. Decomposition of MBT started with the oxidation of –SH groups to sulfate ions. Possible pathways for MBT decomposition by gamma irradiation were proposed. The BOD/COD ratios of MBT samples were increased after radiation, indicating the improvement of biodegradability and reduction of toxicity. [ABSTRACT FROM AUTHOR]

Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields. [ABSTRACT FROM AUTHOR]

Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method. [ABSTRACT FROM AUTHOR]

Experimental results described earlier showed significantly larger relative biological effectiveness (RBE) values for wild-type diploid cells in comparison with radiosensitive mutants. This aspect was further studied in this paper. Diploid yeast cells were irradiated with gamma rays from 60Co and alpha particles from 239Pu in the stationary phase of cell growth. Survival curves and the kinetics of the liquid-holding recovery were measured. When the irradiated cells had completely recovered from potentially lethal damage, they were again exposed to radiation and allowed post-irradiation recovery. The procedure was repeated three times. By use of a quantitative approach - describing the process of recovery as a decrease in the effective radiation dose -, the probability of recovery per unit time and the proportion of irreversibly damaged cells were quantitatively estimated. It was shown that the irreversible fraction of cell injury was increased after repeated exposures to gamma rays, from 0.4 after the first irradiation to 0.7 after the third exposure. The effect was more clearly expressed after exposure to densely ionizing radiation, the corresponding values being 0.5 and 1.0. In contrast, the recovery constant did not depend on the number of repeated irradiations and only slightly depended on radiation quality. It is suggested that the process of recovery from potentially lethal radiation damage itself is not impaired after repeated exposures to both low- and high-LET radiations, and the decrease in the ability of the cell to recover from radiation damage is mainly explained by the increase in the proportion of irreversibly damaged cells. [ABSTRACT FROM AUTHOR]

Abstract: Optical fibers in the readout system for the Large Hadron Collider (LHC) upgrades will operate in a harsh radiactive environment. The fibers within 12 meters from the front-end detectors are exposed up to total ionizing dose of 250 kGy(Si) in their 10 year operational lifetime. In some applications, the fibers within the tracking volume are kept in a cold environment near -25°C. The paper presents the identification of suitable optical fibers for the LHC detector upgrades. Several optical fibers have been tested to 650 kGy(Si) at room temperature with various dose rates of 60Co gamma rays. Two multi-mode fibers and one single-mode fiber have been qualified for use in the LHC upgrades for warm operations. Four optical fibers have been tested to 500 kGy(Si) at -25°C with 27 kGy(Si)/hr 60Co gamma rays. Two SM fibers have been qualified for the LHC upgrades for cold operations. Several optical fibers, including two MM fibers, have been tested up to 11 kGy(Si) at -25°C with 70 Gy(Si)/hr 60Co gamma rays and exhibited moderate radiation induced attenuation (RIA, indicating that all tested fibers are potential candidates for the LHC upgrades for warm and cold operations. [Copyright &y& Elsevier]

Abstract: The PeV gamma ray background produced in the interactions of ultra high energy cosmic rays with the ambient matter and radiations during their propagation in the Milky Way has been calculated in this paper. If the primary ultra high energy cosmic rays are produced from Galactic point sources then those point sources are also emitting PeV gamma rays. We discuss that the detection of galactocentric PeV gamma rays in the future would be a signature of the presence of EeV cosmic accelerators in the Milky Way. [Copyright &y& Elsevier]

Abstract: The development of materials, devices, and methods that allow for the detection of low doses of ionizing radiation is an important research area. In this sense, conjugated polymers have been proposed as promising dosimetric materials. In particular, polymer solutions and composites have been appointed as high-sensitivity systems, but there is no satisfactory understanding of the effects induced by radiation in these systems. Further investigations are therefore necessary for the achievement of more sensitive systems. In this paper, the effect of gamma-ray radiation on different alkyl halide and toluene solutions of poly [2-methoxy-5-(2′-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) is reported. To this end, samples were irradiated with a 60Co gamma-ray source at room temperature, using doses of up to 30Gy. Chloroform, dichloromethane, bromoform, dibromomethane, a mixture of dichloromethane and diiodomethane, and toluene were employed as solvents. The MEH-PPV concentration in the solutions fell in the range of 0.005–0.225mgmL−1. Irradiation of the MEH-PPV alkyl halide solutions was followed by UV–vis spectroscopy measurements, and a blue shift in the main MEH-PPV UV–vis absorption peak was detected. The results revealed that the gamma-ray radiation effects depend on the nature of the solvent and on the concentration of the polymer, thereby indicating that they are associated with the formation of a radical. By selection of a suitable solvent and of an appropriate polymer concentration, a simple dosimeter can be constructed for medical applications as well as other uses. [Copyright &y& Elsevier]

Abstract: In this paper a novel approach to 3-D imaging is discussed. A monochromatic and well collimated gamma rays beam is used to illuminate the body to be imaged; the photons Compton scattered off the body are detected by means of a Germanium strip detector which measures, with high precision, the energy of the photon and its impact position. Inverting the Compton formula, the gamma scattering position along the beam axis is calculated. The electron density of the body may be imaged with this approach. Resolutions and signal to noise ratios are discussed as a function of incident gamma ray energy; a simple simulation is presented. [Copyright &y& Elsevier]

Abstract: Application of radiation techniques for nanotechnology has been known for years. X-ray, electron beam and ion beam lithography are good examples of applications. By using electron beams, ion beams and X-rays structures as small as 10nm can be produced. Ion track membranes with track diameters from 10nm to 100nm are used as such or as templates for electroplating of nanowires of metal, semiconductor and magnetic materials. In the near future X-rays, focused ion beams and electron beams will be used for nanolithography and 3D fabrication; heavy ion beams on the other hand can be useful for fabrication of nanopores and nanowires. The use of radiation has proved to be an essential technique in the fabrication of nanostructures with high resolution as the radiation beams can be focused into few nanometer scales or less. Three groups of products could be considered to be fabricated by radiation techniques: nanoparticles, nanogels and nanocomposites. These and other possible fields of radiation processing applications in nanotechnology are discussed in the paper. [Copyright &y& Elsevier]

Abstract: The aim of this paper is to investigate the rheological properties of polypropylene (PP) modified by ionization radiation (gamma rays) in the presence of two different monomers. The samples were mixed in a twin-screw extruder with ethylene glycol dimethacrylate (EGDMA) or trimethylolpropane trimethacrylate (TMPTMA) with concentration in the range of 0.5–5.0mmol. After that, they were irradiated with 20kGy dose of gamma radiation. The structural modification of polypropylene was analyzed in the melt state by measuring melt flow rate (MFR), η* (complex viscosity) and G′ (storage modulus) in the angular frequency range of 10−1 to 3×102 rads−1. From the oscillatory rheology data, one could obtain the values of η 0 (zero shear viscosity) that would be related to the molar mass. All results were discussed with respect to the crosslinking and degradation process that occur in the post-reactor treatment to produce controlled rheology polypropylene. The resulting polymeric materials were submitted the cytotoxicity in vitro test by neutral red uptake methodology with NCTC L 929 cell line from American Type Culture Collection bank. All modified PP samples presented no cytotoxicity. [Copyright &y& Elsevier]

Abstract: The success of PET systems for dedicated applications such as small animal and breast cancer imaging is largely due to the continuous development of high-resolution, high sensitivity instrumentation for gamma ray detection. This paper reports on some recent advances in the technology together with a brief review of the state-of-the-art of PET systems in these fields. A brief overview of the near-future perspectives is also presented. [Copyright &y& Elsevier]

Abstract: One of several methods used to detect nuclear weapons testing is the monitoring of radioactive xenon in the atmosphere. For high sensitivity, monitoring stations use a complex system of separate beta and gamma detectors to detect beta–gamma coincidences from characteristic radioxenon isotopes in small amounts of xenon extracted from large volumes of air. We report a simpler approach that uses a single phoswich detector, comprising optically coupled plastic and CsI scintillators to absorb beta particles and gamma rays, respectively, and then detect coincidences by pulse shape analysis of the detector signal. Previous studies with a planar prototype detector have shown that the technique can clearly separate beta only, gamma only and coincidence events, does not degrade the energy resolution, and has an error rate for detecting coincidences of less than 0.1%. In this paper, we will present a new phoswich well detector design, consisting of a 1′′ diameter plastic cell enclosed in a 3′′ CsI crystal. Based on Monte Carlo modeling and experimental results, the design will be characterized in terms of energy resolution and its ability to separate beta and gamma only, and coincidence events. [Copyright &y& Elsevier]

Abstract: Owing to its low price and good shielding performance, concrete sees wide use as a radiation shielding material. In concrete structures, cracks occur due to thermal stress, hydration heat, weather, load and other reasons, and shielding performance changes according to the crack width. However, there are no design criteria providing the allowable crack size for shielding. This paper presents the design for a measuring instrument for quantifying the effect of cracks on shielding performance in a concrete body. The correlation between crack width and shielding performance is then deduced through experiments. A measuring system with a collimator is designed and fabricated and a concrete sample with collinear cracking is designed. The surface dose rate increased logarithmically according to the increase in crack width. The present experiment results are used to formulate an attenuation equation for gamma rays in a concrete structure with collinear cracks. The results of this study may be used for developing standards for radiological safety in shielding structures, especially in relation to the shielding margin. [Copyright &y& Elsevier]

Abstract: The next generation large diameter (⩾20m) imaging atmospheric Cherenkov telescopes should allow reduction of the threshold of detection of gamma-rays down to several GeV. At such low energies, the background events can be dominated by cosmic ray electrons. In this paper we estimate the detection energy threshold of a large diameter atmospheric Cherenkov telescope with respect to the diffuse cosmic ray electrons. It is shown that the detection energy threshold of cosmic ray electron induced showers is higher than that for primary gamma showers due to the differences in the development of electromagnetic air showers initiated by these primaries. This can provide a background-free detection region for primary gamma-rays with energy E ⩽5–10GeV, provided that the misclassified events induced by primary hadrons of significantly higher energies and muons are effectively suppressed. [Copyright &y& Elsevier]

Abstract: Over the last 3 years, there has been a growing interest in the development of a new class of fast scintillators such as LaCl3:Ce and LaBr3:Ce. Their superior energy resolution is opening an easier way to improve spatial resolution. In this paper we present the results obtained from the first LaBr3:Ce small gamma camera. It is based on continuous 50×50mm2 crystal, 5mm thick, integral assembled with a Hamamatsu Flat panel PMT. This detector configuration permits the narrowest light distribution with the highest light output in order to obtain the best spatial and energy resolution values, respectively. At the same time, 5mm crystal thickness carries out 80% efficiency at 140keV photon energy. Measurements of spatial resolution are also compared with the analogous ones obtained from another 50×50mm2 LaBr3:Ce crystal, assembled with a 3mm glass optical window. Energy resolution values have been furtherly compared with ones obtained from a LaBr3:Ce 1in. diameter and thickness optimized for spectrometric measurements. The first LaBr3:Ce gamma camera shows excellent intrinsic spatial resolution values such as 0.9mm, with a best energy resolution value of 6.5% at 140keV photon energy. [Copyright &y& Elsevier]

Abstract: Observations of diffuse Galactic γ-ray spectrum by the EGRET instrument reveal an excess above ∼1GeV over the expected γ-ray spectrum calculated under the assumption that the locally observed cosmic-ray (CR) spectra represent the galactic CR spectra. Assuming that Galactic CRs of energy below ∼100TeV are accelerated by supernova remnant (SNR) shock waves and that the shock compression ratio is SNR age dependent, the average source injection spectra from an ensemble of SNRs is calculated both in the inner (330°< l <30°) and outer (30°< l <330°) regions of the galaxy. The calculation considers the SNR age distribution in the galaxy. Injecting these spectra in the galaxy and using a 3-D convection–diffusion equation, the CR electrons and protons spectra in the two galactic regions are obtained and their spectra in the galactic disk are found to be flatter than the observed CR spectra. The diffuse gamma-ray spectrum produced by the interaction of these galactic CRs with the ISM and ISRFs is compared with the experimental data in both the galactic regions. Furthermore, the steepening of the observed local CR spectra from the galactic disk CR spectra are discussed by propagating local CRs having a source spectrum derived using local SNR age distribution (SNRs located within 1.5kpc from the Sun), for a diffusion coefficient D 0 ∼0.3×1027 cm2 s−1 in the local region which is much less than the typical value in the galaxy D 0 ∼(1–10)×1028 cm2 s−1. The results obtained in this paper support the SNR origin of galactic CRs. [Copyright &y& Elsevier]

Abstract: This paper presents the results of an investigation into the spatial distribution of radionuclides of artificial (239,240Pu, 137Cs) and natural (210Pb, 40K) origins in the upper (0–5cm) soil layers on the Baltic coastline of Lithuania (∼5km2 area). The samples were analysed by gamma ray spectrometry and combined radiochemical procedures. The highest 210Pb, 239,240Pu and 137Cs activity concentrations were determined in the forest samples, whereas 40K activity was rather homogeneous across the study area. Relatively high 239,240Pu and 40K activity concentrations were determined along the surf zone. The 210Pb and 137Cs activity concentrations showed a gradual increase from the surf zone to the forest. The average activity concentrations of 239,240Pu, 137Cs, 210Pb and 40K in the beach and forest samples, respectively, were as follows: 0.32±0.08 and 0.74±0.14; 50±4 and 1190±50; 4.7±2.0 and 48±6; 186±15 and 216±17Bq/kg. [Copyright &y& Elsevier]

Compton γ-ray imaging is inherently based on the assumption of γ-rays scattering with free electrons. In reality, the non-zero momentum of target electrons bound in atoms blurs this ideal scattering response in a process known as Doppler broadening. The design and understanding of advanced Compton telescopes, thus, depends critically on the ability to accurately account for Doppler broadening effects. For this purpose, a Monte Carlo package that simulates detailed Doppler broadening has been developed for use with the powerful, general-purpose GEANT3 and GEANT4 radiation transport codes. This paper describes the design of this package, and illustrates results of comparison with selected experimental data. [Copyright &y& Elsevier]

The physical and chemical properties of polymeric materials can be modified by treatment with ionizing radiation in the form of gamma rays, X-rays and energetic electrons. High-energy electron beams are especially useful in this regard. Polymerizing (curing), grafting, crosslinking and chain scissioning reactions can be initiated by irradiation. The results of such reactions can enhance the utility and value of commercial products. Brief reviews of a variety of successful applications are given in this paper. Additional information is provided about reaction yields (G-values), temperature rises during treatment and the radiation stability of common polymers. [Copyright &y& Elsevier]

In this paper, the impact of gamma radiation on one of emerging pharmaceutical pollutant was investigated. Deriving from sartan class, losartan, one of the most consumed antihypertensive drug was irradiated at doses of 0.5–4 kGy in aqueous solutions. The removal of chemical oxygen demand (COD) and total organic carbon (TOC) during the irradiation process reflects that the mineralization efficiency increases with increasing radiation dose. During the mineralization process some aromatic intermediates such as 4-[2-(1H-1,2,3,4-tetrazol-5-yl) phenyl] phenol, 2-butyl-4-chloro-5-(hydroxymethyl) imidazole-1-ol, 2,4′-dihydroxybiphenyl, tetrazole, 1,2,4 benzentriol, 1,4-hydroxyquinone and quinone were identified by LC/MS. These results show that degradation process starts with cleavage of the starting molecule by hydroxyl radicals, which are generated by the radiolysis of water. Based on these observations, a mechanistic schema of losartan was proposed. At the end, losartan kinetic study was performed indicating a pseudo first order degradation process. • Gamma radiation degradation of a Losartan was studied in aqueous solutions. • Identification of degradation by products by LC/MS was performed. • Losartan degradation mechanistic scheme was proposed. • The radiation induced losartan degradation followed pseudo first order kinetics. • Ionizing radiation is a promising way to remove losartan from water and wastewater. [ABSTRACT FROM AUTHOR]

Poly (methyl methacrylate) (PMMA) is widely used in scientific and industrial applications. Because of its favorable properties, it is used in various fields such as optical, medical, and nuclear applications. Effects of ionization radiations on physical properties of PMMA have greatly studied in recent years. However, to the best of our knowledge, there have been no reports on the effects of ionizing radiations, especially the gamma radiation, on the nonlinear optical properties of PMMA. In this paper, for the first time, detection of large and measurable nonlinear refractive index of PMMA after interaction with the gamma radiation is reported. The optical Z-scan technique is used for measuring the nonlinear optical properties of the gamma-irradiated PMMA samples in the 5–300 kGy dose range. It is shown that variation of the induced nonlinear refractive index in this dose range is more or less linear with deposited dose. A new dosimetry method is proposed, which is based on using the Z-scan technique for measuring the nonlinear refractive index of PMMA and obtaining the amount of absorbed dose using this linear response. The name Z-scan dosimetry is coined for this new dosimetry method. • Large nonlinear refractive index of PMMA after gamma irradiation is reported. • It is shown that variation of nonlinear refractive index with gamma dose is linear. • A new dosimetry method, Z-scan dosimetry, is proposed. • The induced nonlinearity is due to the enhanced C C stretching vibration. [ABSTRACT FROM AUTHOR]

The high luminosity upgrade of the Large Hadron Collider, foreseen for 2027, requires the replacement of the ATLAS Inner Detector with a new all-silicon Inner Tracker (ITk). The expected total integrated luminosity of 4000 fb − 1 means that the strip part of the ITk detector will be exposed to a large radiation fluence of up to Φ e q = 1.6 × 1015 1 MeV n e q /cm and an ionizing dose of 0.66 MGy, including a safety factor of 1.5. Radiation-hard n + -in- p micro-strip sensors for use in the ITk have been developed by the ATLAS ITk Strip Sensor collaboration and produced by Hamamatsu Photonics K.K. In this paper, the results obtained from the electrical characterization of the latest barrel ATLAS17LS sensor prototype, before and after irradiation, are shown. Surface properties of the long-strip barrel, full-sized and miniature sensors have been studied before and after proton, neutron and gamma irradiation up to the maximal fluences and radiation doses specified for the ITk Strip tracker. Sensors have been irradiated by protons at CYRIC, Tohoku University (Japan), the Proton Irradiation Facility at CERN, Karlsruhe Inst. Tech. (Germany) and at the University of Birmingham (UK), by neutrons from the Ljubljana TRIGA reactor (Slovenia) and by gamma rays from the 60 Co source in UJP Praha (Czech Republic). It has been verified that the surface radiation damage does not influence the sensor functionality. The breakdown voltage is well above the maximum operational voltage. All the tested surface parameters, such as the inter-strip resistance and capacitance, coupling capacitance and bias resistance satisfy the ATLAS ITk specifications for strip sensors. [ABSTRACT FROM AUTHOR]

An increasing production of drinking water and a significant amount of waste in the form of treated sludge can lead to a serious environmental problem. The high organic content in the sludge, together with the high summer temperatures, results in the enhanced activity of sludge microorganisms, causing severe can cause serious biological pollution. Also, there is a danger due to the potential presence of polyacrylamide, which is very harmful to human health and the environment. In this paper, the influence of different types of ionizing radiation (gamma and e-beam) on microorganisms inactivation in waste sludge from drinking water treatment plants was investigated. The content of heavy metals and polyacrylamide before and after irradiation was determined. It was concluded that the content of heavy metals in the waste sludge obtained from the drinking water treatment plant is significantly lower than the limit values. The concentration of acrylamide, both before and after irradiation, was limit value for sludge to be used as fertilizer. It was found that the dose of 25 kGy inactivates all pathogens in all samples collected directly after coagulation, flocculation, and sedimentation and that the dose of 10 kGy is sufficient to inactivate all pathogens from dewatered samples previously treated with lime. In both cases, the number of microorganisms decreases sharply with increasing radiation dose. • Effect of gamma and e-beam radiation on removal of pathogens from sludge was shown. • Content of heavy metals in sludge was measured. • The concentration of acrylamide in sludge was determined. • The results were compared with the EU Directives. • This sludge complies with the Directives and can be used as fertilizer in agriculture. [ABSTRACT FROM AUTHOR]

The paper presents a comparative analysis and the modeling of the behavior of the viscosities associated with the pasting profile of starches subjected to ionizing radiation processing in the range of 0–20 kGy. The study was performed using both experimental data reported in literature over the last decade and the authors' experimental data. Thus, a mathematical model describing the exponential decrease of the viscosities as the increasing of irradiation dose was proposed. As a result, the values of irradiation dose specific to each starch for each viscosity of pasting profile were determined. These specific irradiation doses are strongly related to the starch sensitivity to irradiation, being influenced by the native starch characteristics (moisture, content, amylose proportion, relative crystallinity and crystallographic pattern). The verification of the model was performed by new experiments of electron beam irradiation on maize starch with irradiation doses up to 20 kGy at a dose rate of 2 kGy/min. Also, an algorithm for the practical use of the developed model and the specific irradiation dose was described. • Pasting profile viscosities vs irradiation doses were modeled by exponential law. • Modeling was performed by using literature data. • Mathematical modeling of viscosities provided values of specific irradiation dose. • Specific irradiation doses characterize the starch response to irradiation. • The dose necessary for obtaining a desired viscosity can be predicted. [ABSTRACT FROM AUTHOR]

Gamma ray is an energetic ionising radiation that can damage living cells as it slows down and transfers its energy to surrounding cells. Lead and concrete have been used as radiation shielding materials. However, it shows that lead toxicity is an important environmental disease and its effects on the human body are devastating. Thus, there is an urgent need to find a sustainable radiation shielding material to safeguard the human and the environment from destructive impact of radiation. High atomic number and high-density materials such as tungsten and concrete are the best effective characteristics of radiation shielding materials. There are numerous experimental and theoretical works were performed on radiation shielding materials. This paper presents a review on the application of lead as radiation shielding material, current safety issues related to lead, current work on radiation shielding material and recent development of new lead-free shielding materials in nuclear medicine. • Lead has been used as a radiation shielding material for radiation protection. • However, lead introduces insidious hazard to human health due to formation of dust particles that affect biochemical systems. • New lead-free materials can replace lead for radiation protection in nuclear medicine. • Recent development of new lead-free radiation shielding materials in nuclear medicine. [ABSTRACT FROM AUTHOR]

In a recent paper, Liu et al. documented the changes in gene expression as stationary phase Deinococcus radiodurans cultures recover from acute exposure to gamma radiation. Given that the biochemical details of the response of D. radiodurans to ionizing radiation are poorly understood, this work represents an important first step towards achieving an understanding of the ionizing radiation resistance in this species. [Copyright &y& Elsevier]

Photographic and cinematographic films of cellulose triacetate safeguarded in historical and cultural institutions are often contaminated by fungi when stored in inadequate conditions of humidity and temperature. The presence of fungi affects the image contained in the films, accelerates the process of biodeterioration and represents a risk to the health of people working with contaminated materials. In addition, another common physicochemical degradation affecting cellulose triacetate films causing deacetylation of polymer chain is called "vinegar syndrome". Considering the dose interval established for the disinfection of cultural heritage materials, in this work the effects of irradiation with gamma rays and electron beam on photographic and cinematographic films of cellulose triacetate were evaluated. Additionally, the thermal stability behavior of the films and the feasibility of crosslinking of CTA films were investigated. Film samples were selected and characterized by FTIR-ATR spectroscopy. Irradiated samples by gamma rays and electron beam with radiation absorbed doses between 6 kGy and 200 kGy were examined by FEGSEM microscopy, UV–Vis spectrophotometry and differential scanning calorimetry (DSC). The results showed that disinfection by gamma and electron beam irradiation, in the dose range of 6 kGy–10 kGy, does not change or modification of main properties of the constitutive materials of photographic and cinematographic films. The applied dose of 50 kGy, both gamma rays and electron beam, indicated a crosslinking effect on the films and can be considered a possibility for the treatment of films affected by the "vinegar syndrome". • Disinfection of photographic and cinematographic films with ionizing radiation. • Crosslinking in CTA films were achieved from gamma and electron beam irradiation. • Ionizing radiation as alternative to treat deteriorated photographic and cinematographic films. [ABSTRACT FROM AUTHOR]