rss_2.0Nukleonika FeedSciendo RSS Feed for Nukleonika Feed degradation of CFCl, CFCl, and CFCl under electron beam irradiation<abstract> <title style='display:none'>Abstract</title> <p>Electron beam treatment technologies should be versatile in the removal of chlorofluorocarbons (CFCs) owing to their exceptional cross sections for the thermal electrons generated in the radiolysis of air. Humidity, dose rates, O<sub>2</sub> concentration, and CFC concentration influence the efficiency of the destruction process under electron beam treatment. Computer simulations have been used to theoretically demonstrate the destruction of chlorotrifluoromethane (CF<sub>3</sub>Cl), dichlorodifluoromethane (CF<sub>2</sub>Cl<sub>2</sub>), and trichlorofluoromethane (CFCl<sub>3</sub>) in the air (N<sub>2</sub> + O<sub>2</sub>: 80% + 20%) in room temperature up to a dose of 13 kGy. Under these conditions, it is predicted that the removal efficiency is in the order CF<sub>3</sub>Cl (0.1%) &lt; CF<sub>2</sub>Cl<sub>2</sub> (7%) &lt; CFCl<sub>3</sub> (34%), which shows the dependence of the process on the number of substituted Cl atoms. Dissociative electron attachment with the release of Cl<sup>–</sup> is the primary process initiating the destruction of CFCs from the air stream. Reactions with the first excited state of oxygen, namely, O(<sup>1</sup>D), and charge-transfer reactions further promote the degradation process. The degradation products can be further degraded to CO<sub>2</sub>, Cl<sub>2</sub>, and F<sub>2</sub> by prolonged radiation treatment. Other predicted products can also be removed through chemical processes.</p> </abstract>ARTICLEtrue design of the gamma blockers for the high-energy beam transport region of the European Spallation Source<abstract> <title style='display:none'>Abstract</title> <p>The European Spallation Source (ESS) is a collaboration of 13 European countries to build the world’s most powerful neutron source for research. The project, situated in the south of Sweden, is approaching the end of the construction phase, and the first scientific results are planned for 2023. This paper gives an overview of mechanical design of the gamma blockers (GBs) in the accelerator to target (A2T) and dump line (DmpL) sections. The presence of GBs in the beam line should limit the gamma radiation emitted from the activated tungsten target and beam dump to allow the safe access of the staff to the machine. The presented design allows for efficient operation and the same shutting time independently of the vacuum status.</p> </abstract>ARTICLEtrue exposure in kindergartens in one Bulgarian district<abstract> <title style='display:none'>Abstract</title> <p>The major part of the radiation dose that humans receive from natural radioactive sources is due to inhalation of radon and its decay products. The study focuses on radon concentration (CRn) investigation in kindergartens and nurseries in the district of Montana. The influence of building characteristics on CRn was evaluated. The measurement of the CRn was performed using passive detectors. The survey was carried out between December 2019 and May 2020 with a total number of 602 detectors. The average value of CRn in the premises of the studied kindergartens and nurseries in this district is 125 Bq·m<sup>−3</sup>, and the geometric mean (GM) value is 88 Bq·m<sup>−3</sup>. The buildings that have built ventilation and sewerage systems have lower CRn. The effective doses of the children and workers were evaluated in order to assess the radon exposure.</p> </abstract>ARTICLEtrue of a Compton backscattering wall defects detection device using the Monte Carlo method<abstract> <title style='display:none'>Abstract</title> <p>In view of the shortcomings of traditional wall defect detection methods, such as small detection range, poor accuracy, non-portable device, and so on, a wall defects detection device based on Compton backscattering technology is designed by Monte Carlo method, which is mainly used to detect the size and location information of defects in concrete walls. It mainly consists of two parts, the source container and the detection system: first, through the simulation and analysis of the parameters such as the receiving angle of the backscattered particles and the rear collimating material of the detector, the influence of the fluorescent X-ray peak of the detector collimating material on the backscattered particle counts is eliminated and the detected error is reduced; second, the ring array detector design, compared with single array detector and surface array detector, can facilitate real-time detection of defect orientation, expanding the single scan range and improving the detection efficiency. After simulation and comparative analysis, the relevant optimal parameters are obtained: the object is detected using a Cs-137 <italic>γ</italic>-ray source with an activity of 6 mCi, and a ring detector consisting of four 0.5-inch cube-shaped CsI scintillator detectors is placed at 150° to receive the backscattered photons. The simulation analysis using the Monte Carlo FLUKA program showed that the maximum depth of wall defect detection is 8 cm, the maximum error fluctuation range of defect depth and thickness is ±1 cm, the overall device weight is &lt;20 kg, and the measurement time is &lt;5 min.</p> </abstract>ARTICLEtrue of low-temperature plasmas formed in low-density gases surrounding laser-produced plasmas<abstract> <title style='display:none'>Abstract</title> <p>Low-temperature plasma production is possible as a result of photoionization using high-intensity extreme ultraviolet (EUV) and soft X-ray (SXR) pulses. Plasma of this type is also present in outer space, e.g., aurora borealis. It also occurs when high-velocity objects enter the atmosphere, during which period high temperatures can be produced locally by friction. Low-temperature plasma is also formed in an ambient gas surrounding the hot laser-produced plasma (LPP). In this work, a special system has been prepared for investigation of this type of plasma. The LPP was created inside a chamber filled with a gas under a low pressure, of the order of 1–50 mbar, by a laser pulse (3–9 J, 1–8 ns) focused onto a gas puff target. In such a case, the SXR/EUV radiation emitted from the LPP was partially absorbed in the low-density gas. In this case, high- and low-temperature plasmas (<italic>T</italic><sub>e</sub> ~100 eV and ~1 eV, respectively) were created locally in the chamber. Investigation of the EUV-induced plasmas was performed mainly using spectral methods in ultraviolet/visible (UV/VIS) light. The measurements were performed using an echelle spectrometer, and additionally, spatial–temporal measurements were performed using an optical streak camera. Spectral analysis was supported by the PGOPHER numerical code.</p> </abstract>ARTICLEtrue and FREE access to plasma physics experiments<abstract> <title style='display:none'>Abstract</title> <p>Remote controlled laboratories had a great push during the COVID-19 pandemic. In fact, they were already out there but lacking in visibility. This external trigger pushed the academy to face a global challenge to start offering remote experiments more consistently and maturely. Instituto Superior Técnico (IST) has been offering several remote experiments since 2000 but with the need for an update due to technological aging. As such, the framework for remote experiments in education (FREE) was created based on new web technologies. In addition to the most diverse experiments that had already been developed, FREE includes two experiments that aimed at advanced-level physics students: the Langmuir probe and the electromagnetic (EM) cavity. Both allow users to configure the various parameters and to access the results in real time or check back later. All this access is done using a browser (on a PC or mobile phone) without the need to install additional software. The results of an experimental execution are stored in a database and are downloadable, allowing users to do various analyses and to determine the corresponding plasma density and temperature. In this paper, we will introduce how FREE was used in the implementation of both experiments and give an insight into their didactic approach, such as: (i) how to perform an experimental execution, (ii) the typical data set obtained with, and (iii) the corresponding analysis necessary for the user to retrieve information from it.</p> </abstract>ARTICLEtrue of Thomson parabola spectrometer in various laser-plasma- and laser-fusion-related experiments<abstract> <title style='display:none'>Abstract</title> <p>The Thomson parabola spectrometer (TPS) [<xref ref-type="bibr" rid="j_nuka-2023-0005_ref_001">1</xref>] is a well-known, universal diagnostic tool that is widely used in laser plasma experiments to measure the parameters of accelerated ions. In contrast to other popular ion diagnostics, such as semiconductor detectors or ion collectors, the TPS is not greatly affected by electromagnetic pulses generated during high-power laser interaction with matter and can be tuned to acquire data in various energy ranges of accelerated ions, depending on the goal of the experiment. Despite the many advantages of this diagnostic device, processing the collected data is a difficult task and requires a lot of caution during interpretation of gathered results. In this work, we introduce the basic principles of operation and data analysis based on the numerical tool created specifically for the TPS designed at the Institute of Plasma Physics and Laser Microfusion, present a range of data obtained during various recent experiments in which our TPS was used, and highlight the difficulties in data analysis depending on the purpose of the experiment and the experimental setup.</p> </abstract>ARTICLEtrue and local parameters of self-compressed plasma streams in external magnetic field<abstract> <title style='display:none'>Abstract</title> <p>The influence of the external axial magnetic field on pinching plasma flows generated by a magnetoplasma compressor (MPC) has been studied using magnetic and electric probes. In the presence of an external magnetic field, temperature measurements show two groups of electrons with different temperatures near the plasma stream core. The external magnetic field leads to a noticeable increase in the electric current in the plasma stream, electron temperature, and the formation of the current-sheet-like structure observed in the MPC for the first time.</p> </abstract>ARTICLEtrue microwave refraction to determine local inhomogeneities of a rotating plasma<abstract> <title style='display:none'>Abstract</title> <p>To determine the local inhomogeneities of a rotating plasma, the method based on microwave refraction was used. The method is based on spectral and correlation analysis of the reflected signals from the rotating plasma layer at normal and inclined microwave incidence. This method allowed us to determine local inhomogeneities of plasma electron density, angles of azimuthal displacement of grooves, and its angular frequency of rotation. Using an additional 4th horn antenna, in contrast to previous works, it was possible to find and analyze two regions with azimuthal inhomogeneities in the rotating plasma. Analysis of the reflected signals shows the presence of four grooves, and the angular frequency of rotation <italic>ω</italic> = 1.16 × 10<sup>4</sup> rad/s was also determined.</p> </abstract>ARTICLEtrue energy partitions in electron–ion PIC simulations of ABC fields<abstract> <title style='display:none'>Abstract</title> <p>We explore the kinetic energy partitions between electrons and ions in the 2-D magnetostatic equilibria called Arnold–Beltrami–Childress (ABC) fields, using particle-in-cell (PIC) numerical simulations. We cover a wider range of ion–electron temperature combinations and get different results compared to previous studies of the Harris-layer-type magnetic reconnection simulations. We find that the initial ion–electron enthalpy ratio is an important indicator. The particle species that dominates the total enthalpy will also dominate the kinetic energy gains and the momentum distribution peaks, but the other species have higher nonthermal energy fractions because both species show similar maximum energies.</p> </abstract>ARTICLEtrue derived from -terphenyl in the methyltributylammonium bis[(trifluoromethyl)sulfonyl]imide ionic liquid saturated with carbon dioxide: Pulse radiolysis study<abstract> <title style='display:none'>Abstract</title> <p>Radiation-induced processes in ionic liquid (IL) methyltributylammonium bis[(trifluoromethyl)sulfonyl] imide ([MeBu<sub>3</sub>N][NTf<sub>2</sub>]) solutions containing <italic>p</italic>-terphenyl (TP) and saturated with carbon dioxide (CO<sub>2</sub>) were studied using nanosecond pulse radiolysis technique with UV-vis detection. The transient absorption spectra generated in these solutions were assigned to TP radical anions (TP<sup>•−</sup>) and triplet excited states (<sup>3</sup>TP*). Saturation of [MeBu<sub>3</sub>N][NTf<sub>2</sub>] solutions with carbon dioxide efficiently takes out presolvated electrons <inline-formula> <alternatives> <inline-graphic xmlns:xlink="" xlink:href="graphic/j_nuka-2022-0007_ieq_001.png"/> <mml:math xmlns:mml="" display="inline"><mml:mrow><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:msubsup><mml:mtext>e</mml:mtext><mml:mrow><mml:mtext>presolv</mml:mtext></mml:mrow><mml:mo>−</mml:mo></mml:msubsup></mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math> <tex-math>( {{\rm{e}}_{{\rm{presolv}}}^ - } )</tex-math> </alternatives> </inline-formula> and solvated electrons <inline-formula> <alternatives> <inline-graphic xmlns:xlink="" xlink:href="graphic/j_nuka-2022-0007_ieq_002.png"/> <mml:math xmlns:mml="" display="inline"><mml:mrow><mml:mrow><mml:mo stretchy="false">(</mml:mo><mml:mrow><mml:msubsup><mml:mtext>e</mml:mtext><mml:mrow><mml:mtext>solv</mml:mtext></mml:mrow><mml:mo>−</mml:mo></mml:msubsup></mml:mrow><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:mrow></mml:math> <tex-math>( {{\rm{e}}_{{\rm{solv}}}^ - } )</tex-math> </alternatives> </inline-formula> . On the other hand CO<sub>2</sub> is not a scavenger of excited states of TP (<sup>1</sup>TP*, <sup>3</sup>TP*), which in the reaction with triethylamine (TEA) leads to the formation of TP<sup>•−</sup>.</p> </abstract>ARTICLEtrue Sr quantification method based on the Bateman equation for routine laboratory work<abstract> <title style='display:none'>Abstract</title> <p>Artificially introduced into the environment <sup>90</sup>Sr is highly radiotoxic, so its content levels in foodstuff and biota require constant monitoring for radiological protection. Most analytical procedures used for <sup>90</sup>Sr determination are time-consuming, and therefore, a faster approach is needed. Employing the Bateman equation enables more efficient exploitation of the secular equilibrium between <sup>90</sup>Sr and its daughter radionuclide <sup>90</sup>Y in the calculations. This article describes a method for computing the <sup>90</sup>Sr activity concentration, while accounting for <sup>90</sup>Y activity. The developed approach was tested and validated in terms of its applicability in everyday analysis.</p> </abstract>ARTICLEtrue upgrading of the nanosecond pulse radiolysis setup and construction of laser flash photolysis setup at the Institute of Nuclear Chemistry and Technology in Warsaw, Poland<abstract> <title style='display:none'>Abstract</title> <p>Modification of pulse radiolysis (PR) setup and construction of a new laser flash photolysis (LFP) setup at the Institute of Nuclear Chemistry and Technology (INCT) is described. Both techniques are dedicated to studying fast reactions in real time by direct observation of transients. Time resolution of the PR setup at INCT was ~11 ns, limited by the duration of the electron pulse. Implementation of a new spectrophotometric detection system resulted in a significant broadening of experimental spectral range with respect to the previous setup. Noticeable reduction of the noise-to-signal ratio was also achieved. The LFP system was built from scratch. Its time resolution was ~6 ns, limited by the duration of a laser pulse. LFP and PR were purposely designed to share the same hardware and software solutions. Therefore, components of the detection systems can be transferred between both setups, significantly lowering the costs and shortening the construction/upgrading time. Opened architecture and improved experimental flexibility of both techniques were accomplished by implementation of Ethernet transmission control protocol/Internet protocol (TCP/IP) communication core and newly designed software. This is one of the most important enhancements. As a result, new experimental modes are available for both techniques, improving the quality and reducing the time of data collections. In addition, both systems are characterized by relatively high redundancy. Currently, implementation of new equipment into the systems hardly ever requires programming. In contrast to the previous setup, daily adaptations of hardware to experimental requirements are possible and relatively easy to perform.</p> </abstract>ARTICLEtrue of intrapulse energy switching in standing-wave electron linac<abstract> <title style='display:none'>Abstract</title> <p>For the development of an effective cargo-scanning system, an intrapulse energy switching has been tested at the National Centre for Nuclear Research (NCBJ) with the possibility to change the beam energy within a 4 μs pulse of the linear electron accelerator (linac). Modification of the electron energy is achieved through the beam-loading effect in a standing-wave accelerating structure equipped with a triode gun. Construction of the machine and the achieved results are presented in this article.</p> </abstract>ARTICLEtrue of an energy-resolving detection system for mammography applications: A preliminary study<abstract> <title style='display:none'>Abstract</title> <p>Breast cancer remains one of the major causes of mortality among female cancer patients. This fact caused a spark in the medical field, which in turn helped to improve the diagnostic and treatment of breast cancer patients over the years making this field always active with new ideas and innovative methods. In our study, a new method was explored using an energy-resolving detection system made from a NaI (Tl) scintillation detector to detect the gamma photons from an Am-241 radiation source to try and construct an image by scanning the American College of Radiology (ACR) mammography phantom. In addition to the experimental work, a Geant4 Application for Tomographic Emission (GATE) toolkit was used to investigate more complex options to improve the image quality of mammographic systems, which is limited by the experimental setup. From the experimental setup, the researchers were able to construct an image using the 26.3 keV and the 59.5 keV energy photons, to show the largest size tumour (12 mm) in the ACR phantom. With an improved setup in the simulation environment, the majority of the ACR phantom tumours was visible using both energy windows from the 26.3 keV and the 59.5 keV, where the 26.3 keV yielded better quality images showing four tumours compared to three when using 59.5 keV. The simulation results were promising; however, several improvements need to be incorporated into the experimental work so that the system can generate high-resolution mammographic images similar to the ones obtained by the GATE simulation setup.</p> </abstract>ARTICLEtrue of electron beam irradiation on filtering facepiece respirators integrity and filtering efficiency<abstract> <title style='display:none'>Abstract</title> <p>The outbreak of the COVID-19 pandemic has shown that the demand for medical masks and respirators exceeds the current global stockpile of these items, and there is a dire need to increase the production capacity. Considering that ionizing radiation has been used for sterilization of medical products for many years and electron beam (EB) irradiation enables the treatment of huge quantities of disposable medical products in a short time this method should be tested for the mask’s decontamination. In this work, three different filtering facepiece respirators (FFRs) were irradiated with electron beams of 12 kGy and 25 kGy. The results confirmed that the decrease in filtration efficiency after irradiation of all respirators results from the elimination of the electric charge from the polypropylene (PP) fibers in the irradiation process. Moreover, the applied doses may affect the thermal stability of PP fabrics, while filtering materials structure and integrity have not changed after irradiation.</p> </abstract>ARTICLEtrue gamma-ray methods for industrial process evaluation: A simulation study<abstract> <title style='display:none'>Abstract</title> <p>Radioisotope applications in industrial process inspection and evaluation using gamma-ray emitters provide otherwise unavailable information. Offering alternative gamma-ray sources can support the technology by complementing sources’ availability and radiation safety. This work proposes to replace gamma-ray from radioisotopes with prompt gamma-ray from the interaction of neutrons with stable isotopes injected into the industrial process or with the structural material of the industrial process equipment. Monte Carlo N-Particle Transport Code (MCNP5) was used to simulate the irradiation of two-phase flow pipes by <sup>252</sup>Cf neutron source. Two simulations were run for each pipe, with and without mixing the liquid phase with the stable isotope <sup>157</sup>Gd. The detected gamma-ray spectra were analysed, and images of the two phases inside the pipes were produced. The images were compared to images obtained from simulations of gamma transmission measurement using <sup>60</sup>Co. Furthermore, results for prompt gamma computed tomography (CT) were presented and discussed. The studies’ outcomes indicate the potential of prompt gamma-ray to carry out the sealed sources applications of gamma transmission measurements and imaging.</p> </abstract>ARTICLEtrue on water transport in quasi two-dimensional porous systems using neutron radiography<abstract> <title style='display:none'>Abstract</title> <p>The spontaneous wetting and drying of flat porous samples of linen, cotton and synthetic textiles were studied using dynamic neutron radiography (DNR). The progress of the wetting process of the media was delineated from the obtained neutron dynamical radiography images. The results of the investigation reveal a non-classical behaviour of kinetics of wicking of these materials. The character of the wetting kinetics is discussed in terms of the fractal character of the tortuosity of fabric capillaries.</p> </abstract>ARTICLEtrue synthesis of gold nanoparticles in HEMA-based hydrogels: Potentialities for imaging nanocomposites<abstract> <title style='display:none'>Abstract</title> <p>This article reports on the radiolytic synthesis of nanocomposites containing gold nanoparticles (AuNPs) within two types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA): (i) plain networks with various contents in ethylene glycol dimethacrylate (EGDMA), as a cross-linker and (ii) stimuli-responsive (SR) networks prepared from these monomers copolymerized with [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) to confer pH-switchable swelling. Hydrogels were prepared by photopolymerization with well-defined composition and a high degree of monomer conversion using two experimental procedures, as xerogels or in aqueous solution. Besides MADQUAT, acrylic acid (AA) or <italic>N</italic>-isopropylacrylamide have been tested as copolymers, yielding pHor temperature-sensitive hydrogels, respectively. Isothermal swelling in water was affected by monomer composition. Electron beam (EB) irradiation at doses up to 100 kGy of poly(HEMA) xerogels and water-swollen networks prepared with 0.5 wt% of EGDMA had a moderate impact on swelling characteristics and thermomechanical properties of the plain materials, whereas small amounts of extractables were formed. Poly(HEMA)-based nanocomposites containing AuNPs were successfully obtained by EB irradiation of samples swollen by aqueous solutions of Au(III). The effects of dose and cross-linking density on the formation of AuNPs were monitored by UV-visible spectroscopy. Irradiation at well-defined temperatures of the Au(III)-loaded SR hydrogels induced the formation of nanoparticles with size-dependent features, whereas the efficiency of Au(III) reduction at 10 kGy was not significantly affected by the network structure. EB-induced reduction of Au(III) in poly(HEMA) hydrogels using a lead mask to generate well-defined patterns yielded coloured and long-lasting images in the zones where the nanocomposite was formed.</p> </abstract>ARTICLEtrue International Conference on Development and Applications of Nuclear Technologies, NUTECH-2020, Warsaw, Poland, 4–7 October 2020