Radioactive Sources Research Articles

Overproduction Of Fibrinolysis Enzyme Produced By Mutant Pseudomonas Aeruginosa Compared To Wild Type Pseudomonas Aeruginosa

Objective: The aim of the study is to increase the production of fibrinolytic enzyme produced by pseudomonas aeruginosa after mutagenesis with physical mutagens compared to the wild type. Study design: Cross-sectional in descriptive study design and case–control in analytical study design. Backgrounds: P. aeruginosa is a ubiquitous gram-negative aerobe. Its opportunistic pathogen that infects patients with cystic fibrosis, burn, wounds, immunodeficiency, chronic obstructive pulmonary disorder (COPD), cancer. Fibrinolytic enzyme is a factor that lysis fibrin clots. This fibrinolytic factor has prospective use totreat cardiovascular diseases such as stroke and heart attack. Thrombotic disorders are the main cause of death world. Methodology: Study patients, specimens, collection of bacterial isolates. Plasma agar plate assay, Skim milk agar assay, Radial caseinolytic assay, Preparing magnetizing Water. Exposure P. aeruginosa to radioactive sources, lasers and magnetic water. Determination of optimal bacterial isolate for the fibrinolytic enzyme production. Results: Increased when P. aeruginosa were exposed to Na23 at an efficiency of 10 µci. Also exposed to 10 ml of magnetic water during 48 hr., then exposed to a cobalt radioactive source during 3 hr., another radioactive source is Cs137, Co60 and Sr90 in 1 hr. during 48 hours with exposure to laser and magnetized water. Conclusion: Conclude that the overproduction of fibrinolytic enzyme (clot-dissolving enzyme) increased when P. aeruginosa were exposed to Na23, Cs137, Co60 and Sr90 with exposed to laser and magnetized water in certain period.

Development of [formula omitted]/[formula omitted]/[formula omitted] discrimination with the phoswich detector using improved charge comparison method

Both pulse shape discrimination methods based on temporal difference characteristic and phoswich detectors are well-known and effective for particles discrimination, so the combination and further improvement are significant for better performance. In this paper, a phoswich detector combining YAG(Ce) and CsI(Tl) was constructed for α/β/γ discrimination using various techniques including two machine learning algorithms and an improved charge comparison method that further exploited the difference in the decay rate of pulse tail. The detector was designed with Geant4, simulating the suitable sizes of scintillators, and a high-speed digitizer was used for the collection of pulses that were from three radioactive sources. The results among the α (β) and γ rays had the figure of merit values greater than 2, simultaneously with an optimal 1.68 of the improved method that had more than twice the performance comparing the original 0.69 for α/β identification, which showed the detector is able to discriminate α, β and γ rays in mixed radiation field effectively.

Rapid and efficient separation of radioactive cesium ion/other radioactive ions by reduced graphene oxide membrane

Separation of cesium ions from other radioactive ions is of great significance for recycling and utilization of radioactive sources, facilitating the management of highly radioactive liquid waste (HLW), as well as for environmental protection. We achieved a highly selective and efficient separation of binary mixtures of 137Cs/60Co, Cs+/Co2+, Cs+/Ni2+, and Cs+/Zn2+ using amino-hydrothermal reduced graphene oxide membranes. The separation factor for non-radioactive binary mixtures is up to 4290, with a water permeance of 50.8 L m−2 h−1 bar−1. The separation factor for radioactive 137Cs/60Co is 623, which is somewhat underestimated due to the detection limit of the high-purity germanium spectrometer. The rGO membranes has the high water permeance of 72.4 L m−2 h−1 bar−1, with a thickness of ∼300 nm. The rGO membrane achieved effective separation of cesium and cobalt ions over a wide range of cesium-to-cobalt ion concentration ratios, with the best results achieved at a concentration ratio of 100:1 for cesium and cobalt. In addition, the rGO membranes showed outstanding stability. The superior performance is attributed to the amino hydrothermal treatment, which reduced oxygen functional groups and directly inserted nitrogen atoms into the GO lattice, ultimately forming stable narrow nanochannels conducive to the size-sieving effect. The findings show that the rGO membranes have excellent separation performance due to their size-sieving effect, and this work has great potential for rapid and efficient treatment of radioactive liquid waste.

Validation of GAMOS Monte Carlo simulation for 131Cs brachytherapy source in water and dosimetric characterization of solid water, bone, and brain tissues

PurposeThe treatment of brain tumours using permanently implanted 131Cs has become more frequent since GammaTile brachytherapy platform was cleared by the U.S. Food and Drug Administration (FDA). Current treatment planning systems (TPS) (BrachyVision v11.0.47, Varian Medical Systems, Palo Alto, CA, USA) used clinically do not account for anatomical heterogeneities. GAMOS Monte Carlo simulation was validated for the dose deposited by 131Cs in water and used to accurately determine the dose deposited in simulated human tissues, including bone and brain tissue, as well as in Solid Water (SW) phantom material. MethodGAMOS was validated and benchmarked for dose deposited by 131Cs (CS-1 Rev2) in water. The evaluation performed included air-kerma strength, radial dose function, anisotropy function, and dose rate constant based on the recommendation of TG-43U1S2 protocol. Dosimetric simulation of the 131Cs brachytherapy source was also performed in SW, bone, and brain tissue using GAMOS. Conversion factors were calculated by the ratio of the dose rate constant from water to SW, bone, and brain tissue, respectively. ResultResults for dose in water were benchmarked with MCNP simulation and experiential data published in the TG-43U1S2. The dose rate constant in water was 1.039 ± 0.017 cGy h−1 U−1 which is consistent with the results used to determine the TG-43U1S2 consensus data. The conversion factor of water to SW, water to the bone, and water to brain tissue were 0.936, 1.15, and 0.964, respectively. ConclusionOther Monte Carlo (MC) simulation codes, such as MCNP, have been previously used in the literature to determine the dose deposited by 131Cs. In this work, doses deposited by 131Cs radioactive sources were successfully simulated using GAMOS MC simulation. To our knowledge, this is the first time that GAMOS was used to simulate the dose deposited by 131Cs seed. MC simulation of dose for brachytherapy sources is especially important to accurately estimate the dose deposited in high Z materials such as skull bone, which may be widely different than the dose calculated by the TG-43U1S2 formalism.

Development of electron detectors for the BRAND experiment

The BRAND experiment employs detectors that utilize gas ionization and plastic scintillators, integrated with custom-designed front-end electronics, aimed at measuring the correlation coefficients in neutron beta decay. This article focuses on the characterization and performance of a newly developed electron detector prototype featuring custom-designed front-end electronics. The characterization results indicate an weak gain dependency of the scintillator when exposed to a radioactive source, varying along its length and width.

Identification of Distorted Gamma-Ray Signature Patterns Using Digital Filtering and Auto-Associative Memory Implemented with a Hopfield Neural Network

The detection and identification of radioactive sources in search applications involve analyzing passive gamma-ray emissions from high-level radioactive materials. This process uses a mobile detector-spectrometer in a complex field test environment. Recently, the use of artificial intelligence for gamma-ray spectrum analysis has shown promising results. However, challenges persist in identifying isotopic signatures from spectral measurements that may be distorted due to source shielding, random variations in natural radioactive background, or insufficient measurement time to obtain clear spectral lines. This paper presents a novel intelligent signature recognition method that combines digital filtering techniques with an artificial Hopfield Neural Network (HNN). The HNN leverages auto-associative memory to store training sample patterns and match them with incoming gamma spectra from distorted sources. It restores the testing sources’ measurements by finding the closest matching signature patterns in the spectral library. Before HNN recognition, the measured spectrum undergoes preprocessing with a digital image filter to reduce fluctuations. Performance of the proposed method is evaluated using a set of gamma-ray spectra measured with a sodium iodide detector. The data collected include measurements from six pure samples: 241Am, 60Co, 137Cs, 192Ir, 239Pu, and 235U, which are used for training and validation (i.e. six cases). Additionally, the data set contains 24 distorted synthesized sources with various fluctuating backgrounds. Test results demonstrate the potential of the proposed method to accurately recognize the correct isotope with high precision, achieving an accuracy rate exceeding 85%. Furthermore, the proposed method exhibits superior performance compared to the conventional multiple regression fitting and simple feedforward neural network methods.

Improving Compton camera imaging of multi-energy radioactive sources by using machine learning algorithms for event selection

Event selection and background reduction for Compton camera imaging of multi-energy radioactive sources has been performed by employing neural networks. A Compton camera prototype with detectors made of LaBr3 crystals coupled to silicon photomultiplier arrays was used to acquire experimental data from a circular array of 22Na sources. The prototype and two arrays of 22Na sources were simulated with GATE v8.2 Monte Carlo code, to obtain data for neural network training. Neural network models were trained on simulated data for event classification. The optimum models were found by using Weights & Biases platform tools. The trained models were used to classify simulated and real data for selecting signal events and rejecting background prior to image reconstruction. The models performed well on simulated data. The image obtained with experimental data showed an improvement with respect to event selection with energy cuts. The method is promising for Compton camera imaging of multi-energy radioactive sources.

Radiation and mechanical performance of cementitious materials containing ecofriendly nano laboratory waste glass

This study helps in managing waste glass and greening the environment by incorporating laboratory waste glass into mortar production to make an eco-friendly shielding material against gamma rays. The efficiency of using waste glass powder as a cement replacement or addition in mortar production was studied by using two waste glass sizes: micro glass (particle size range from 10.09 to 24.73 μm) and nano glass (particle size range from 10.57 to 26.42 nm) to design different mortar specimens with varying percentages of fine glass powder from 0 to 30%. Compressive strength and flexure strength were evaluated to determine mechanical properties. The results indicated that adding WGP to mortar positively affects the characteristics of cementitious composites. The linear and mass attenuation coefficients of the samples were experimentally determined using a NaI detector and various radioactive sources (Am-241, Ba-133, Eu-152, Cs-137, and Co-60) with gamma energies ranging from 59.53 to 1332 keV. The obtained coefficients were then compared to the theoretical values of the composites using XCOM software to verify their accuracy. Additionally, the half-value layer, tenth-value layer, mean free path, and effective atomic number were computed. Furthermore, the results revealed that the mortar sample with 30% nano additive glass was the most effective in reducing gamma radiation.

Lessons learned from establishing and running a Mössbauer laboratory in industry

Mössbauer spectroscopy offers unique capabilities for primary industry sectors such as mining, mineral processing, and steelmaking, as well as in environmental services and advanced manufacturing. However, there are three key limiting factors: the time required to record a single spectrum, the challenges of managing an additional radioactive source on company premises, and the lack of personnel skilled in analysing Mössbauer spectra and understanding its operation. More commonly used techniques such as XRD, SEM, or XRF have technical staff who can interpret data with support from standard libraries and user-friendly software packages. In contrast, Mössbauer spectroscopists, who often hold degrees in Physics or Chemistry, typically emerge from academic settings and are less commonly employed in industry. This paper addresses the current challenges limiting the widespread adoption of Mössbauer laboratories in the industry and proposes potential solutions to overcome these obstacles. These solutions include promoting internships for undergraduate and postgraduate students familiar with Mössbauer spectroscopy in industrial settings, increasing investment in software development, hosting seminars and workshops to educate industry professionals on the capabilities of Mössbauer spectroscopy, and providing ongoing support from the scientific community to industries interested in operating spectrometers in their facilities.

Analysis of The Influence of Models of Individual Physical Processes and Phenomena on the Calculation Time of the Source Term in Severe Accidents

Dependence of the CPU time needs for calculation of the source term during a severe accident at nuclear power plants with WWER reactors from the individual physical processes and phenomena used as part of the calculation tools similar to the SOСRAT/V3 severe accident code is investigated. This analysis allows revealing the most expensive models in terms of runtime. The simplification of these models can ensure the greatest acceleration of the calculation. The relevance of the task draws from the need to develop new or adapt existing calculation tools for assessing the intensity of radioactive emission sources for the tasks of emergency preparedness and response considering the specific requirements for the accuracy of numerical estimates and time to obtain them. The paper demonstrates the possibility of reducing CPU time without significant loss of accuracy of the numerical estimates by simplifying the spectrum of aerosols sizes. The efficiency of the proposed approach is demonstrated by the example of modeling the Phebus FPT1 experiment.

Development and Experimental Validation of a Heat Transfer Model for Spilled Molten Salt Pools

A spill of radionuclide-bearing molten salt is one of the major postulated events that needs to be analyzed for liquid fluorine salt–cooled high-temperature reactor (FHR) or molten salt reactor licensing purposes. In this postulated event, radioactive source term materials (RSTMs) in the molten salt are discharged from the reactor vessel to the reactor building. The release of RSTMs from the spilled salt pool to the gas space in the reactor building is expected to be controlled by the cooling behavior of the spilled salt, including the growth and shrinkage of the solid crust on the surface of the spilled salt pool. This paper presents a simulation model for spilled salt pool heat transfer and validation efforts. The validation data come from two molten salt spill tests that were performed recently: the PELE2 test by the Rapid Experimental Laboratory of Kairos Power LLC (KP) and the Argonne salt cooling test conducted by Argonne National Laboratory. The former was a large-scale test involving kilograms of molten spilled FLiNaK salt, and the latter was a relatively smaller-scale test targeting various processes associated with a salt spill event. Both tests generated valuable data sets that can be used to assess salt cooling and validate evaluation models. This paper provides a new one-dimensional model that can simulate the cooling process of a spilled salt pool as well as the thermal responses of heat structures, such as the stainless steel liner and the concrete below the salt. The model has been implemented as part of KP-SAM code, which is a branch of the systems code SAM specific to KP FHR. The simulation results of the model are compared with the data of the PELE2 and Argonne tests, and reasonable agreements are observed between the model and test data.

Advancements in Biological Dosimetry Techniques for Surge Response to Radiation Emergencies in Ghana

The awareness of the use of biodosimetry to estimate external radiation doses received by individuals and in radiation oncology, nuclear medicine, diagnostic, and interventional radiology has gained traction in recent years. At present Ghana is poised to integrate about 1GW of nuclear power into its electricity mix by 2034. The increased awareness of biodosimetry is probably due to increased radiological threats and incidents, medical and forensic applications, the quest to strengthen emergency response to unplanned radiation exposures such as radiological accidents, and the malevolent use of radioactive sources. Biodosimetry capabilities would play an effective role during public health management of radiation emergencies for rapid dose estimation and help to medically categorize the exposures for the purpose of prioritizing treatment of the affected persons. Moreover, it will also serve to provide reassurance and psychological support for the “worried-well”. Biodosimetry methods and infrastructure can also be utilized for various applications, including molecular research, medical cytogenetics, and forensics. This write-up assesses the status of biodosimetry methods and infrastructure capabilities available at the Ghana Atomic Energy Commission (GAEC), which could be leveraged during radiological or allied scenarios.

Henri Coutard (1876-1950): A Pioneer of Fractionated Radiotherapy Regimens.

Henri Coutard was a prominent French roentgen therapist (radiation therapist). He was a pioneer physician and scientist who established the development of the "protracted-fractional method"of radiation dosing. He treated laryngeal cancer with super-voltage x-rays and also published data on five-year survival rates while his contemporary physicians indulged in treating cancer with radioactive sources. Due to his significant contribution regarding the use of fractionated dose regimens to treat cancer, in today's world most of the tumors are treated using the same principle which is in itself a great achievementin the field of radiation oncology.Due to his work, present-day radiotherapy practice is focused on therapeutic ratios to treat cancer.

Monte Carlo simulation of shielding materials in storage drums for 241Am-Be disused sealed radioactive sources

Disused Sealed Radioactive Sources (DSRS) containing neutron sources such as 241Am-Be require careful management due to neutron radiation. However, finding readily available and effective combination layer shielding materials for practical use to safely contain 241Am-Be can be challenging. The main objective of this study is to investigate the configuration of shielding materials and determine the maximum activity of 241Am-Be sources that can be safely stored in a 200-L drum. A three-layer shielding approach using a 200-L drum as a storage container, with sequential layers of lead (Pb), polyethylene (PE), and ordinary Portland concrete (OPC), achieves the lowest dose rates compared to other combination sequences, as shown by Monte Carlo simulations. With a fixed lead thickness and varying polyethylene and ordinary Portland concrete thicknesses, Monte Carlo simulations using the Particle and Heavy Ion Transport code System (PHITS) demonstrate that this drum design can safely accommodate activities ranging from 22.01 Ci to 72.92 Ci of 241Am-Be. The fitted model equation determines the required polyethylene thickness for any activity within this range. Additionally, case-based simulation results indicate that Indonesia's total inventory of 241Am-Be DSRS can be stored in three 200-L drums with a polyethylene thickness of 15 cm. This configuration meets international standards, ensuring the dose rate does not exceed 2 mSv/h at the surface and 0.1 mSv/h at 1 m from the drum's surface.

Heavy ion detection in thermally and non-thermally treated CR-39 detectors: Fission fragment ranges and etchable track lengths

For the first time, etched track diameter and over-etched track diameter (OETD) measurements have been used to determine etchable track lengths in thermally treated poly allyl diglycole carbonate (PADC) in the form of CR-39, as well as heavy ion track ranges in non-thermally treated samples. These heavy ions are produced spontaneously from 252Cf radioactive source as fission fragments. Isochronal heating experiment was conducted on CR-39 detectors prior to their irradiation to 252Cf radioactive source. In a reverse sequence, another set of detector films was first subjected to 252Cf irradiation and then thermally treated as described above. The diameters of etched heavy ion tracks in non-thermally treated and thermally treated CR-39 detectors have been measured as a function of etching time at different heating temperatures and times. The fission fragment ranges in non-thermally treated CR-39 detectors determined using the OETD method were found to be 17.7 ± 0.2 μm for the heavy group and 21.8 ± 0.3 μm for the light group, whereas the etchable track lengths in thermally treated detectors are by far lesser than that those of non-thermally treated ones. The results of heavy ion ranges in non-thermally treated detectors are in excellent agreement with theoretical calculations based on SRIM code. While in the case of the etchable track lengths of these heavy ions in thermally treated detectors, there is no such theoretical data for comparison with experiment till present.

Field Test of the MiniRadMeter Gamma and Neutron Detector for the EU Project CLEANDEM.

In the framework of the H2020 CLEANDEM project, a small robotic vehicle was equipped with a series of different sensors that were developed for the preliminary inspection of areas possibly contaminated by radiation. Such unmanned inspection allows to identify dangerous locations prior to the possible start of human operations. One of the developed devices, named the MiniRadMeter, is a compact low-cost sensor that performs gamma and neutron radiation field mapping in the environment. The MiniRadMeter was successfully tested in a simulated field mission with four "hidden" radioactive sources and a neutron generator. In this work, we describe the test procedure and the results, which were supported by the outcome of dedicated Monte Carlo simulations.

Cosmic radiation monitoring in aeronautics and astronautics

The growth of the aerospace industry has made the detection of cosmic radiation essential. That led to a proposal for the development of an optoelectronic detector of cosmic radiation. This will allow continuous measurement of acceptable levels of radiation. The device is currently in its initial development phase, focusing on the detection of ionising radiation. Tests have been carried out with high-energy radiation simulators in the form of natural radioactive sources, confirming the performance of the overall system. The cosmic ray sensor of the study has numerous potential applications, particularly in the aerospace industry. Crew safety could be enhanced by a miniature sensor that measures the absorbed dose of cosmic radiation. Existing passive methods of dose measurement have been ineffective because they provide information about radiation with a delay of several weeks. Active monitoring of irradiation levels enables ongoing control of the dose taken, which is crucial for employee health.

Experimental, simulation, and theoretical investigations of gamma and neutron shielding characteristics for reinforced with boron carbide and titanium oxide composites

This study investigates the radiation shielding properties of composites containing polyester resin, boron carbide and titanium oxide in varying proportions. The radiation transmittance of the produced composites was measured using radioactive sources 241Am, 137Cs, 133Ba, 60Co, and 22Na across a photon energy range of 59.5 keV–1332.5 keV. To analyze radiation permeability, experimental geometry was simulated using Monte Carlo-based computer codes Monte Carlo N-Particle (MCNP), Particle and Heavy Ion Transport code System (PHITS) and FLUktuierende KAskade or Fluctuating Cascade (FLUKA), and the experimental data were compared with simulation results and theoretical data obtained from WINXCOM. The findings demonstrated a high degree of consistency between experimental, simulation, and theoretical results. Notably, the BCTiO50 sample, which included a 50% addition of TiO2, emerged as the most effective in photon radiation shielding. In addition to gamma shielding, the neutron shielding properties of the produced composites were evaluated using the FLUKA code, revealing that the BCTiO0 sample, with the highest percentage of boron, provided the best neutron shielding. This analysis included composites with decreasing boron carbide content by 10%, 20%, 30%, 40%, and 50% by weight, each replaced with titanium oxide, showcasing the potential applications of these polymer composites in radiation shielding.

Energy calibration of LaBr3 detectors using inherent radioactivity

In general, the energy calibration of gamma-ray detectors is carried out by using radioactive sources with well-known emission lines. The fact that the scintillator material LaBr3 includes natural radioactivity is often taken advantage of to perform an energy calibration without the need to handle an external radioactive source. For this purpose, the emission energy of photons to be detected in peaks has to be well known. Though the energies of the emission lines of the relevant isotope 138La and further information on radioactive contaminations are published with high precision, there are inconsistencies in the literature concerning the effective energies of observed photon peaks caused by inherent radioactivity. In this article, the actual peak positions are published as a result of high-precision measurements. The potential and limitations of an energy calibration of LaBr3 detectors based on the inherent radioactivity are discussed, as the emission lines of 138La are detected in clusters rather than single, clearly defined lines.

Abatement of ionizing radiation for superconducting quantum devices

Ionizing radiation has been shown to reduce the performance of superconducting quantum circuits. In this report, we evaluate the expected contributions of different sources of ambient radioactivity for typical superconducting qubit experiment platforms. Our assessment of radioactivity inside a typical cryostat highlights the importance of selecting appropriate materials for the experiment components nearest to qubit devices, such as packaging and electrical interconnects. We present a shallow underground facility (30-meter water equivalent) to reduce the flux of cosmic rays and a lead shielded cryostat to abate the naturally occurring radiogenic gamma-ray flux in the laboratory environment. We predict that superconducting qubit devices operated in this facility could experience a reduced rate of correlated multi-qubit errors by a factor of approximately 20 relative to the rate in a typical above-ground, unshielded facility. Finally, we outline overall design improvements that would be required to further reduce the residual ionizing radiation rate, down to the limit of current generation direct detection dark matter experiments.