Hasil untuk "Radioactivity and radioactive substances"

W. Dong, V. Manea, R. Ferrer et al.

We present the design and simulation of a prototype gas cell for in-gas-jet laser-ionization and spectroscopy studies using the low energy branch of the SPIRAL2-S$^3$ radioactive-ion-beam facility. The prototype aims to demonstrate the possibility to reduce the extraction time of radioactive ions from the gas cell, while implementing a controlled neutralization mechanism, necessary for laser-spectroscopy studies. Different simulation methods of ion processes in gas are comparatively discussed. Design considerations and detailed simulations of the ion extraction time and efficiency are presented. A study of the dynamics of electrons obtained in the gas cell by ionization is also performed to assess the achievable electron densities.

Sara Lourenço da Silva, Marcos Paulo Cavaliere de Medeiros, Aneuri Souza de Amorim

The Brazilian Army's responsibility for nuclear defense operations, as defined in the National Defense Policy and Army Strategic Plan, has led to advancements in this field, as the establishment of the Gamma Monitor Calibration Laboratory (LCG) at the Institute of Chemical, Biological, Radiological, and Nuclear Defense (IDQBRN) within the Brazilian Army Technology Center (CTEx). The LCG calibrates radiation monitors for troops in defense operations and emergencies. It has secured accreditation from the Evaluation Committee for Testing and Calibration Services (CASEC) and is currently seeking certification from the National Institute of Metrology, Standardization, and Industrial Quality (INMETRO) to enhance its Cs-137 calibration capabilities for radiological protection. All activities must adhere to relevant ABNT NBR standards. The primary aim of this paper is to develop a computational model of the LCG that integrates the irradiation system, utilizing the Monte Carlo N-Particle (MCNP) radiation transport code. This model will initially be employed to evaluate backscattered radiation and will remain available for future applications and testing. This simulation was performed using MCNP5, and the graphical input file editor (VISED) was used to verify the defined geometry. The modeling was based on construction data and the specifications of the internal equipment. The input file was created and utilized in the code, providing the output file with the ambient dose equivalent normalized per photon emitted at the source. Then, the result was adjusted for source activities and converted into a dose rate. All simulated values ​​were lower than the experimental ones, for example, for the condition without attenuation at 1 m, the simulated value is 3,0816 mSv/h, while the experimental is 3,1930 mSv/h.

Cibele Bugno Zamboni, Dalton Nogueira da Silva Giovanni, Simone Michaela Simons

The coxal fluid of the tick species Ornithodoros brasiliensis (O. brasiliensis) was subjected to detailed chemical analysis using Instrumental Neutron Activation Analysis (INAA) and Energy Dispersive X-ray Fluorescence (EDXRF). These complementary techniques allowed the identification and quantification of key elements such as sodium (Na), chlorine (Cl), potassium (K), and zinc (Zn), along with others like sulfur (S), phosphorus (P), and iron (Fe). The study demonstrated the consistency between the two analytical methods and revealed significant data about the tick's physiological adaptations related to fluid excretion and blood meal processing. Additionally, the absence of heavy metals in the analyzed samples was confirmed. Understanding the composition of coxal fluid is vital for interpreting metabolic processes and exploring its toxicological potential, given the aggressive nature of O. brasiliensis, known to cause severe health impacts on humans and animals. This research contributes to advancing knowledge about tick biology and supports the development of public health measures against tick-borne hazards.

MAYELLE LIMA, Giovana Dias Silva, Patrícia et al.

The construction of an in vitro model that can accurately demonstrate the conditions found in vivo requires the production of a series of complexities that often transcend various areas of knowledge. In this context, the present study employed three-dimensional culture by magnetic aggregation to build a model that minimally satisfactorily represented conditions for studying cellular behaviors present in the tumor environment related to cell death and duplication. Thus, functionalized iron oxide nanoparticles were used for culturing tumor spheroids containing breast adenocarcinoma cell line (MCF7) and human fibroblast (HF002-J) within their structure. The spheroids were divided into concentration categories for each cell line, and after a screening process, the concentrations with greater stability were irradiated or received doses of a drug with known antitumor activity for treatment. The models were studied through X-ray diffraction (XRD), Transmission electron microscopy (TEM), cytotoxicity assays, and fluorescence microscopy.  The obtained results proved to be a viable alternative for the analysis of cell viability, cytotoxicity, and the morphology of tumor spheroids.

S. Mandal, S. Gope, S. Das et al.

Gas Electron Multiplier (GEM) is a cutting edge Micro Pattern Gaseous detector (MPGD) technology suitable as tracking device in high rate Heavy-Ion (HI) experiments for their good spatial resolution and most importantly high rate handling capability. The performance studies including the detector efficiency, gain, energy resolution and also the stability study under high radiation are most important aspects, to be investigated before using the detector in any experiment. In this work, all of the above mentioned aspects are investigated using a 55Fe X-ray source for a single mask triple GEM chamber prototype operated with premixed Argon/CO2 (Ar/CO2) gas mixture in 70/30 volume ratio. In this article, particularly the stability in efficiency using a radioactive source is discussed in detail.

Lise Tingstad, Brett Sandercock, Signe Nybø

D. A. Zavyalov, L. Yu. Krestinina

The objective of the study is to analyze solid cancer mortality and estimate the risk value of solid cancer mortality in the offspring of parents irradiated in the Southern Urals, depending on the dose to the parents' gonads as well as to conduct a preliminary assessment of the mortality risk from cancer of individual locations depending on the gonadal dose. The issue of the transgenerational effects of the human gonad exposure is still very important. There exists conclusive evidence of the presence of such effects in experimental animals. However, there is no proof of the existence of these effects in humans despite a great number of research on this subject. International scientific community and international organizations, UNSCEAR and ICRP being among them, regard this issue as the one that has not been solved yet and requires further studies. Urals Cohort of offspring of the population exposed on the Techa River and on the territory of the East Ural radioactive trace was established in the Urals research Center for Radiation medicine in 2022. The key feature of the cohort is the exclusion of the offspring with postnatal exposure. The size of the cohort as of September 2023 is 31,154 persons. The number of person-years over the whole follow-up period from 1950 through 2020 is 1 226 380. Mean dose to the gonads of mothers of all the cohort members is 41 mGy, to those of the fathers' — 35 mGy, mean combined gonad dose is 76 mGy. Over the whole follow-up period 3,774 deaths from all causes including 284 deaths from solid cancers were registered in the cohort. The mean age of the cohort members at the end of the follow-up period was 42 years. The risk of death was analyzed using Poisson regression by the programs of the EPICURE statistical software package. Three models of dose dependence were tested: linear, quadratic, and linear-quadratic models of paternal gonadal dose, maternal gonadal dose, and total gonadal dose. Mortality risk analysis of all solid cancers in the offspring cohort showed no statistically significant effect with parental gonadal dose (we have obtained positive although statistically insignificant values of solid cancers mortality risk) which is consistent with the results of other studies in human populations. At the same time, the analysis for the first time obtained a statistically significant linear dependence of the solid cancer mortality risk in offspring with father's age over 45 years depending on the dose to the father's gonads. The excess relative risk of death was 8.09/Gy, (0.51-22.93), p < 0.05. Also, for the first time, evidence of dose dependence of the mortality risk of lung cancer in male offspring on maternal gonadal dose, paternal gonadal dose, and combined gonadal dose was obtained. The values of excess relative risk of lung cancer and 95% confidence intervals according to the linear model were 5.39/Gy (0.46; 15.56) from paternal gonad dose, 4.36/Gy (0.15; 13.48) from maternal gonad dose, and - 3.95/Gy (0.55; 12.14) from combined gonad dose. Point risk estimates of lung cancer at this stage are characterized by wide confidence intervals and require additional studies to assess the influence of possible effect modifiers, but with a high degree of probability indicate the presence of dose dependence of this effect. Increasing the follow-up period and attained age, will increase the number of cancers in the future and will reduce dose response uncertainties and provide more accurate estimates of the risk of death in the offspring cohort.

A. V. Petryakova, L. A. Chipiga, I. A. Zvonova et al.

Radiopharmaceutical therapy with 131I has been one of the most common types of radiopharmaceutical therapy  for  many  years.  Radiation  safety  of  the  public  is  ensured  by  limiting  the  patient  contacts  until  the radiological parameters are reduced to the established criteria. To increase the availability of the radiopharmaceutical therapy with 131I, softer patient release criteria for 131I have been proposed. However, early patient release may increase exposure to the public, e.g. in transport. The aim of the work is to evaluate the radiation exposure  from  patients  with 131I -MIBG  and  Na131I on  the  public  in  transport  considering  the  generation  of biological waste. In this work, 131I excretion from the body of patients in transport was evaluated for different scenarios of patient travel to the place of residence. As a result, it was found that mitigation of patient release criteria leads to an increase in the effective dose to the public in transport and an increase in the 131I activity excreted with patient waste. The specific activity in the tanks of biotoilets in transport, generated after the pas -sage of a patient with injected 131I -labeled radiopharmaceuticals, exceeds the limit value of classifying liquid waste as radioactive. To optimize radiation protection of the public, it is advisable to apply a differentiated approach to release patients after therapy with 131I: to group non-resident patients into a separate category retaining for them the established release criterion (without mitigation) to minimize the radiation impact on the public.

Caitlin Condon, Philip Jensen, Patrick Royer et al.

The U.S. Department of Energy (DOE) Office of Integrated Waste Management is planning for the eventual transportation, storage, and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) from nuclear power plant and DOE sites. The Stakeholder Tool for Assessing Radioactive Transportation (START) is a web-based, geospatial decision-support tool developed for evaluating routing options and other aspects of transporting SNF and HLW, covering rail, truck, barge, and intermodal infrastructure and operations in the continental United States. The verification and validation (V&V) process is intended to independently assess START to provide confidence in the ability of START to accurately provide intended results. The V&V process checks the START tool using a variety of methods, ranging from independent hand calculations to comparison of START performance and results to those of other codes. The V&V activity was conducted independently from the START development team with opportunities to provide feedback and collaborate throughout the process. The V&V analyzed attributes of transportation routes produced by START, including route distance and both population and population density captured within buffer zones around routes. Population in the buffer zone, population density in the buffer zone, and route distance were all identified as crucial outputs of the START code and were subject to V&V tasks. Some of the improvements identified through the V&V process were standardizing the underlying population data in START, changing the projection of the population raster data, and changes to the methodology used for population density to improve its applicability for expected users. This collaboration also led to suggested improvements to some of the underlying shape file segments within START.

Harish Gadey, Caitlin Condon, Steven Maheras et al.

The United States Department of Energy (U.S. DOE) is planning for the transportation, storage, and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) from commercial nuclear power plants and other U.S. DOE sites. The Stakeholder Tool for Assessing Radioactive Transportation (START) is a web-based, geospatial decision-support tool developed for evaluating routing options and other aspects of transporting SNF and HLW via barge, train, truck, and intermodal surface transport in the continental United States. The verification and validation (V&V) effort is intended to independently assess START to provide confidence in the ability of the tool to accurately provide intended outputs. The results selected for the V&V effort of the START code include those identified as crucial outputs by subject matter experts. Outputs from START such as shape files and keyhole markup language (KML) files are analyzed using a geodesic computation using the WSG-84 ellipsoid model. Most of the V&V efforts are aimed towards examining and comparing the total length reported in the various files in the START tool. This work also focuses on the development of V&V methodologies for various outputs that could be replicated by the end user on a set of user-defined routes. Over 150 origin destination pairs were run as part of this effort to test the functionality of the START tool. In addition to presenting results using an independent geodesic computation, this work will provide a comparison of the total route lengths between START version 3.3 and the previous release of START (version 3.2.2).

Caitlin Condon, Kacey McGee, Harish Gadey et al.

The U.S. DOE Office of Integrated Waste Management is planning for the eventual transportation, storage, and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW) from nuclear power plants and DOE sites. The Stakeholder Tool for Assessing Radioactive Transportation (START) is a web-based, geospatial decision-support tool developed for evaluating routing options and other aspects of transporting SNF and HLW, covering rail, truck, barge, and intermodal infrastructure and operations in the continental United States. The verification and validation (V&V) process is intended to independently assess START and provide confidence in the ability of START to accurately provide intended results. The V&V efforts included an independent analysis of select outputs through other geographic information system (GIS) programs including QGIS. The V&V efforts have focused primarily on the route buffer zone population values as well as the route lengths reported in START. The efforts include developing a V&V methodology for each output type that an independent user could replicate through the user interface for a small number of routes as well as more automated methodologies that reduce the number of interactions with the GIS user interfaces. Independent analysis of the routes showed excellent agreement between the START outputs for population within the route buffer zone and the length of the routes. Over 200 test routes were evaluated; in all cases, the percent difference in the population within the buffer region was less than +/- 5%, and most cases were below +/- 1%. The V&V work is ongoing and other START features that are undergoing independent analysis include population density within the route buffer zone as well as reported doses for the segments within the START code.

Torsten Schmiermund

Manuel García-León

Hortência de Jesus Ferreira, Carlos Alberto Zeituni, Maria Eduarda Zaganin Rigo et al.

The conservative surgery for impalpable breast cancer requires an intraoperative localization method that guides the identification and correct excision of the lesion. The aim of this study is to comparatively analyze two intraoperative breast localization technologies, wire guided localization (WGL) and radioactive seed localization (RSL), regarding their surgical efficacy through the outcomes of surgical margins, intraoperative re-excision, reoperation and recurrence. To this end, a systematic search was realized in databases for clinical trials that match with the study eligibility criteria. The selected studies were evaluated for their methodological quality; the data were then collected and quantitatively synthesized. The results comprised thirty-eight studies that match the eligibility criteria. The main outcomes reported demonstrating that the RSL is at least equivalent to the WGL in efficiency rates. These results confirm the method applicability for impalpable breast lesions surgery in an effective way, in addition to presenting organizational optimization of radiology and surgery services by allowing the surgery to be performed up to two months after seed implantation.

Max da Silva Ferreira, Everton Rodrigues Silva, Cláudia Lúcia de Pinho Maurício

The Instituto de Radioproteção e Dosimetria (IRD) is implementing an automatic neutron individual monitoring system, which uses albedo dosemeters from the Alnor manufacturer. For practical purposes, the occupational neutron fields have been divided into four application areas, named N1, N2, N3 and N4, as recommended in the German standard DIN 6802-4. For each area, specific Workplace Correction Factor (WCF), as a function of the ratio between photon dose responses measured in the incident and albedo component of the albedo dosemeter (Di/Da), must be used. This study proposes an algorithm for evaluating the photons and neutrons HP(10) values for the Alnor albedo system. It uses WCF × Di/Da curves previously defined by the authors, using MCNPX code simulations of the neutron dosemeter response for several occupational neutron fields. The methodology for calculating all uncertainties involved in the photon and neutron HP(10) assessment is also shown. Before the routine use of this system at IRD, several tests and calibrations are being carried out. This manuscript presents a case study carried out at the Angra I and Angra II power plants in 14 different fields (N1 application area). The results of the Alnor system are compared with those from the albedo system currently in routine use at the IRD. The average value of the ratio between the measurements with the Alnor system and the IRD system was 0.97 for photon HP(10), and 0.84 for neutron HP(10). Considering an expanded uncertainty to 95% confidence level, all results agree with each other.

Bruno Tappiz, Edson Gonçalves Moreira

Measurement uncertainty was estimated following the EURACHEM guide (Quantifying Uncertainty in Analytical Measurement) for the elements As, Br, Cl, Co, Cr, Cs, Fe, K, Mg, Mn, Na, Rb, Sb, Se and Zn determined by Instrumental Neutron Activation Analysis (INAA) and for the elements Cd, Hg and Pb determined by Atomic Absorption Spectrometry (AAS) in the fillet of the most consumed fish species at São Paulo city, Brazil. INAA expanded uncertainties ranged from 1.0 to 21% and the main contributions were due the counting statistics of sample and pipetted standards. For AAS, expanded uncertainties ranged from 6.5 to 13% and the main contributions were associated to the calibration curves. Uncertainty results were compared with the standard deviations of the mass fraction in the fishes (n = 10). Due to the wide variability in the mass fraction in the analyzed fish tissues, explained by factors such gender, age, fat content and fishing location of the specimens of each species, standard deviations were greater than expanded uncertainties, which means that the natural variability of the elements determined is greater than the data dispersion associated with the analytical techniques. Hence the used techniques were adequate for the fish fillet samples analyses.

Antonio Nappa, Christopher Hobbs, Andrea Lanzi

What do Apple, the FBI and a Belgian politician have in common? In 2003, in Belgium there was an election using electronic voting machines. Mysteriously one candidate summed an excess of 4096 votes. An accurate analysis led to the official explanation that a spontaneous creation of a bit in position 13 of the memory of the computer attributed 4096 extra votes to one candidate. One of the most credited answers to this event is attributed to cosmic rays i.e.(gamma), which can filter through the atmosphere. There are cases though, with classical computers, like forensic investigations, or system recovery where such soft-errors may be helpful to gain root privileges and recover data. In this paper we show preliminary results of using radioactive sources as a mean to generate bit-flips and exploit classical electronic computation devices. We used low radioactive emissions generated by Cobalt and Cesium and obtained bit-flips which made the program under attack crash. We also provide the first overview of the consequences of SEUs in quantum computers which are today used in production for protein folding optimization, showing potential impactful consequences. To the best of our knowledge we are the first to leverage SEUs for exploitation purposes which could be of great impact on classical and quantum computers.

Roland Diehl, Maria Lugaro, Alexander Heger et al.

The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter recurrently re-processes metal-enriched stellar ejecta into the next generation of stars. The study of cosmic nucleosynthesis and of this matter cycle requires the understanding of the physics of nuclear reactions, of the conditions at which the nuclear reactions are activated inside the stars and stellar explosions, of the stellar ejection mechanisms through winds and explosions, and of the transport of the ejecta towards the next cycle, from hot plasma to cold, star-forming gas. Due to the long timescales of stellar evolution, and because of the infrequent occurrence of stellar explosions, observational studies are challenging. Due to their radioactive lifetime of million years, the 26Al and 60Fe isotopes are suitable to characterise simultaneously the processes of nuclear fusion reactions and of interstellar transport. We describe and discuss the nuclear reactions involved in the production and destruction of 26Al and 60Fe, the key characteristics of the stellar sites of their nucleosynthesis and their interstellar journey after ejection from the nucleosynthesis sites. We connect the theoretical astrophysical aspects to the variety of astronomical messengers, from stardust and cosmic-ray composition measurements, through observation of gamma rays produced by radioactivity, to material deposited in deep-sea ocean crusts and to the inferred composition of the first solids that have formed in the Solar System. We show that considering measurements of the isotopic ratio of 26Al to 60Fe eliminate some of the unknowns when interpreting astronomical results, and discuss the lessons learned from these two isotopes on cosmic chemical evolution.

Stefaan Pommé, Krzysztof Pelczar

In recent work, Milian-Sanchez et al. observed fluctuations in radioactive decay rate measurement series, and after excluding environmental influences (measured indoors) as root causes, they looked for possible correlations with astrophysical variables. In spite of the authors efforts to investigate possible influences of environmental parameters (such as ambient temperature, pressure and humidity) on the detectors stability, it turns out that the influence of ambient humidity on the instrumentation has been underestimated.

Brit Salbu, Ole Christian Lind