Production Of Radioactive Isotopes Research Articles

Study of cosmogenic activation above ground of Ar for DarkSide-20k

The production of long-lived radioactive isotopes due to the exposure to cosmic rays on the Earth's surface is an hazard for experiments searching for rare events like the direct detection of galactic dark matter particles. The use of large amounts of liquid argon is foreseen in different projects, like the DarkSide-20k experiment, intended to look for Weakly Interacting Massive Particles at the Laboratori Nazionali del Gran Sasso. Here, results from the study of the cosmogenic activation of argon carried out in the context of DarkSide-20k are presented. The induced activity of several isotopes, including 39Ar, and the expected counting rates in the detector have been deduced, considering exposure conditions as realistic as possible.

Radioactivity study of EAST structural materials based on neutron activation system

The plasma operation in the Experimental Advanced Superconducting Tokamak (EAST) would generate 2.45 MeV neutrons and a small fraction of 14 MeV neutrons. Neutrons react with structural materials, leading to the production of radioactive isotopes. The identification of nuclides and the determination of radioactive activity are of great significance for radiation protection and fusion material applications. In this study, structural materials including stainless steel 316L(SS316L), stainless steel 304L(SS304L), aluminum(Al), tungsten(W) and copper(Cu) were transported to the activation terminal for fusion neutron irradiation. The gamma ray spectra were measured using high-purity germanium (HPGe) detector, and the main radioactive nuclides of SS316L and SS304L are 56Mn, while the main radioactive nuclide of Al is 28Al. For Cu and W, the main radionuclides resulting from neutron reactions are 66Cu and 187W, respectively. The uncertainty of the radioactivity is 2.27∼7.94 % for W, 1.95∼5.84 % for SS316L, 2.10∼6.07 % for SS304L, 0.68∼1.69 % for Al and 2.59∼6.75 % for Cu. The specific activity of radionuclides is proportional to neutron yield, so the material activation is the main source of radiation dose during irradiation with high-yield neutron. The neutron activation coefficients of SS316L, SS304L, Al, Cu and W are 2.74538 × 10−14, 3.6411 × 10−14, 2.50711 × 10−12, 1.76506 × 10−12 and 3.51725 × 10−14, respectively. The coefficient represents the radioactive activity generated by each fusion neutron. In addition, the predicted activity was calculated using FISPACT program and compared with experiments.

Investigating characteristics of neutrons from accelerator-driven compact source using novel target of compressed beryllium-powder

The study was conducted at the cyclotron laboratory of the Tomsk Polytechnic University, on the use of a new form of target utilized in the production of fast-neutrons. The flux of fast-neutrons emitted by a novel target of beryllium powder compressed in a copper mold has been measured using Al and Fe foils as detectors. The change in the neutron flux in terms of the deuteron energy was studied by using thin aluminum filters. The increase of neutron flux reached about 60% when comparing with results obtained previously by our team when only the Be-target was used, this increase referred to the reaction Cu (n, 2n). In addition, comprehensive experimental graphs were obtained using our results beside other results from related literatures. It was found that they almost agree with the experimental results from the previous studies at energies less than 12 MeV, but then the neutron flux starts to increase when using a target of Be-powder compressed in a copper mold. The difference may become greater at energies above 15 MeV and the enhancement could be many times larger. Furthermore, fitted curves and their equations were obtained for the neutron flux as a function of deuteron-energy in the energy-range between 0.5 and 50 MeV. Also, the average energy of neutrons can be calculated from the derived equations for deuteron-ions in the energy-range from 2.6 to 40 MeV. The results of this study are new and promising, so that when confirming these results at higher energies above 15 MeV, we can obtain a greater neutron yield when using a target of Be-powder compressed in a copper mold or other metals with higher cross section of the reaction (n, 2n). The high intensity beams of fast-neutrons could be employed in many crucial applications, such as radiotherapy, production of radioactive isotopes, and more.

Augmented reality-assisted gesture-based teleoperated system for robot motion planning

Purpose The study proposed a human–robot interaction (HRI) framework to enable operators to communicate remotely with robots in a simple and intuitive way. The study focused on the situation when operators with no programming skills have to accomplish teleoperated tasks dealing with randomly localized different-sized objects in an unstructured environment. The purpose of this study is to reduce stress on operators, increase accuracy and reduce the time of task accomplishment. The special application of the proposed system is in the radioactive isotope production factories. The following approach combined the reactivity of the operator’s direct control with the powerful tools of vision-based object classification and localization. Design/methodology/approach Perceptive real-time gesture control predicated on a Kinect sensor is formulated by information fusion between human intuitiveness and an augmented reality-based vision algorithm. Objects are localized using a developed feature-based vision algorithm, where the homography is estimated and Perspective-n-Point problem is solved. The 3D object position and orientation are stored in the robot end-effector memory for the last mission adjusting and waiting for a gesture control signal to autonomously pick/place an object. Object classification process is done using a one-shot Siamese neural network (NN) to train a proposed deep NN; other well-known models are also used in a comparison. The system was contextualized in one of the nuclear industry applications: radioactive isotope production and its validation were performed through a user study where 10 participants of different backgrounds are involved. Findings The system was contextualized in one of the nuclear industry applications: radioactive isotope production and its validation were performed through a user study where 10 participants of different backgrounds are involved. The results revealed the effectiveness of the proposed teleoperation system and demonstrate its potential for use by robotics non-experienced users to effectively accomplish remote robot tasks. Social implications The proposed system reduces risk and increases level of safety when applied in hazardous environment such as the nuclear one. Originality/value The contribution and uniqueness of the presented study are represented in the development of a well-integrated HRI system that can tackle the four aforementioned circumstances in an effective and user-friendly way. High operator–robot reactivity is kept by using the direct control method, while a lot of cognitive stress is removed using elective/flapped autonomous mode to manipulate randomly localized different configuration objects. This necessitates building an effective deep learning algorithm (in comparison to well-known methods) to recognize objects in different conditions: illumination levels, shadows and different postures.

Cosmogenic activation of sodium iodide

The production of radioactive isotopes by interactions of cosmic-ray particles with sodium iodide (NaI) crystals can produce radioactive backgrounds in detectors used to search for rare events. Through controlled irradiation of NaI crystals with a neutron beam that matches the cosmic-ray neutron spectrum, followed by direct counting and fitting the resulting spectrum across a broad range of energies, we determined the integrated production rate of several long-lived radioisotopes. The measurements were then extrapolated to determine the sea-level cosmogenic neutron activation rate, including the first experimental determination of the tritium production rate: $(80\ifmmode\pm\else\textpm\fi{}21)\text{ }\text{ }\mathrm{atoms}/\mathrm{kg}/\mathrm{day}$. These results will help constrain background estimates and determine the maximum time that NaI-based detectors can remain unshielded above ground before cosmogenic backgrounds impact the sensitivity of next-generation experiments.

Reaction synthesis of SrTiO3 mineral-like ceramics for strontium-90 immobilization via additional in-situ synchrotron studies

The paper presents spark plasma sintering-reaction synthesis (SPS-RS) of SrTiO3-based mineral-like ceramics with a perovskite structure, which is promising for immobilization of Sr-90 radionuclides. Detailed time-resolved study of phase transformations taking place in the reactive mixture (SrCO3 and TiO2) within 20–1000 °C temperature range was conducted using both in situ heating synchrotron XRD and TGA. Structure and composition dependence on consolidation temperature was revealed by the means of SEM and EDX. We determined optimal temperature conditions for rapid formation of SrTiO3 ceramics with density – 4.49 g cm−3, Vickers hardness – up to 6.2 GPa, compressive strength – 279 MPa, and strontium leaching rate of 10−5–10−6 g cm−2·day. These results clearly show strong applied potential of the presented material for radioactive waste management and isotope production fields.

Radioactive background for ProtoDUNE detector

The Deep Underground Neutrino Experiment (DUNE) is a leading-edge, international experiment for neutrino science and proton decay studies. This experiment is looking for answers regarding several fundamental questions about the nature of matter and the evolution of the universe: origin of matter, unification of forces, physics of black holes. Two far detector prototypes using two distinct technologies have been developed at CERN. The prototypes are testing and validating the liquid argon time projection chamber technology (LArTPC). In neutrino physics, as well as in any experiment with rare interaction rate, the good knowledge of the radioactive backgrounds is important to the success of the study.Muons and neutrons represent the main sources of background for this kind of experiments. In this paper, we have considered two sources of neutrons: cosmic neutrons and neutrons coming from the accelerating tunnel. Also, cosmic muons are taken into account. The contribution of these particles to the production of radioactive isotopes inside the active volume of the detector in comparison to the one corresponding to muons is shown. Also, simulations of nuclear reactions for the processes of interest for investigating the radioactive background due to the lack of measurements or insufficient experimental data are presented. Most of the results presented in this paper will be of interest for the future underground DUNE experiment.

Light fragment and neutron emission in high-energy proton induced spallation reactions * *Supported by the National Natural Science Foundation of China (11722546, 11675226) and the Talent Program of South China University of Technology

The dynamics of high-energy proton-induced spallation reactions on target nuclides of 56Fe, 58Ni, 107Ag, 112Cd, 184W, 181Ta, 197Au, and 208Pb are investigated with the quantum molecular dynamics transport model motivated by the China initiative Accelerator Driven System (CiADS) in Huizhou and the China Spallation Neutron Source (CSNS) in Dongguan. The production mechanism of light nuclides and fission fragments is thoroughly analyzed, and the results obtained thereby are compared with available experimental data. The statistical code GEMINI is employed in conjunction with a transport model for describing the decay of primary fragments. For the treatment of cluster emission during the preequilibrium stage, a surface coalescence model is implemented into the model. It is found that the available data in terms of total fragment yields are well reproduced in the combined approach for spallation reactions both on the heavy and light targets. The energetic light nuclides (deuteron, triton, helium isotopes etc) mainly created during the preequilibrium stage are treated within the framework of surface coalescence, whereas their evaporation is described in the conventional manner by the GEMINI code. With this combined approach, a good overall description of light clusters and neutron emission is obtained, and some discrepancies with the experimental data are discussed. Possible production of radioactive isotopes in the spallation reactions is also analyzed, i.e., the 6,8He energy spectra.

Yttrium Oxide Freeze-Casts: Target Materials for Radioactive Ion Beams.

Highly porous yttrium oxide is fabricated as ion beam target material in order to produce radioactive ion beams via the Isotope Separation On Line (ISOL) method. Freeze casting allows the formation of an aligned pore structure in these target materials to improve the isotope release. Aqueous suspensions containing a solid loading of 10, 15, and 20 vol% were solidified with a unidirectional freeze-casting setup. The pore size and pore structure of the yttrium oxide freeze-casts are highly affected by the amount of solid loading. The porosity ranges from 72 to 84% and the crosslinking between the aligned channels increases with increasing solid loading. Thermal aging of the final target materials shows that an operation temperature of 1400 °C for 96 h has no significant effect on the microstructure. Thermo-mechanical calculation results, based on a FLUKA simulation, are compared to measured compressive strength and forecast the mechanical integrity of the target materials during operation. Even though they were developed for the particular purpose of the production of short-lived radioactive isotopes, the yttria freeze-cast scaffolds can serve multiple other purposes, such as catalyst support frameworks or high-temperature fume filters.

Neutron Radiation Effects on Lubricants and O-Rings for Target and Accelerator Applications

Lubricants and O-rings are necessarily used for the construction of many accelerator-driven facilities as spallation sources or facilities for the production of radioactive isotopes. During operation, such component will absorb high doses of mixed neutron and gamma radiation, that can degrade their mechanical and structural properties. Experimental radiation damage tests of these components are mandatory for the construction of the facility. Methodologies for irradiation in nuclear reactor mixed fields and post-irradiation examination of lubricating oils, greases and O-rings were developed and are here presented. Samples were characterized with standard mechanical and physical-chemical tests. Parametric studies on the dose rate effects have been performed on O-rings. A case studies for a specific O-ring application in a gate valve has been developed. Some of the tested samples showed a dramatic change of their properties with dose, while others remain stable. Results were collected on nine commercial greases, on one oil and on four commercial elastomeric O-rings. The most radiation resistant among the selected products are now considered for application in facilities under construction. The main mechanisms of neutron and gamma radiation damage on these polymers were investigated at the mechanical and structural level.

Study of the Nuclear Structure for Some Target Nuclei Used in the Production of Beta-Emitting Radioactive Isotopes for the Fabrication of Nuclear Batteries

The nuclear structure of 40Ar, 112Cd, 133Cs, 151Eu, 154Sm, and 226Ra target nuclei used in nuclear battery technology was investigated. These nuclei are widely used for the radioisotope thermo-electric generator space studies and for betavoltaic battery microelectronic systems. For this purpose, some nuclear static properties were calculated. In particular, the single particle radial nuclear density distribution, the corresponding root mean square radii, neutron skin thicknesses, and binding energies were calculated within the framework of Hartree-Fock approximation with Skyrme interaction. The bremsstrahlung spectra produced by the absorption of beta particles through the betavoltaic process and backscattered photons spectrum were also studied. All the obtained results were compared with available experimental data.

DERICA Project and Strategies of the Development of Low-Energy Nuclear Physics

Possible strategies of the development of low-energy nuclear physics in Russian Federation on the basis of the DERICA (Dubna Electron–Rare Isotope Collider fAcility ) project is examined. DERICA is a multiuser multipurpose facility for the production and study of radioactive isotopes (RI). In the research program of DERICA, emphasis is placed on studying RI in collector rings, but a stage-by-stage implementation of the program of DERICA would make it possible to address a wide range of fundamental problems at each stage of its development at the cutting-edge level. The ambitious goal of creating an electron–radioactive ion collider for studying basic properties of RI in electron–ion scattering is proposed for the final stage of development of DERICA.

Research study of possibility producing radioisotope Mo-99 in the active core of the BN-600 reactor using an irradiated assembly with a high flux of thermal and resonance neutrons

It is fact that production of secondary fuel isotopes (plutonium) is carried out in fast neutron reactors, and the possibility of production of non-fuel radioactive isotopes for use in medicine and industry is being considered. BN-600 has a high power density in the core. This makes it possible to achieve a high rate of fission of target nuclei, which is especially important in the case of the production of radioisotopes, due to their short half-life. To meet the growing demand for isotopes, it is planned to use irradiation devices in high-power sodium fast reactors. This type of irradiation device assumes a massive production of the necessary isotopes. The paper considers the design of irradiation devices for the production of molybdenum-99 isotope in the BN reactor. The presented design of the irradiation assembly contains a moderator in order to combine the advantages of the high neutron flux inherent in fast reactors and the thermal neutron spectrum inherent in thermal reactors.

Thermohydraulic simulation of a channel with targets for production of radioactive isotopes in the IVV-2M nuclear reactor

The importance of radioisotope products usage in industry, science and medicine is underlined. The necessity of safety ensuring and radiation protection optimization while transporting the containers with radioactive isotopes is postulated. The information on isotope products making in the IVV-2M nuclear reactor of Research Institute of Nuclear Materials, JSC, from the beginning of 1990-ies is given. The data on application properties of Selenium 75 isotope are presented. The requirements to the thermohydraulic conditions of Se 75 isotope production in the nuclear reactor are formulated. The stages of a solid model development of a target for Se-75 isotope production as a part of an irradiation device of IVV-2M nuclear reactor are described. The results of hydraulic simulation of the coolant flow for various ways of devices arranging in the irradiation channel of the reactor are given. The analysis of thermohydraulic processes was performed with the help of SolidWorks Flow Simulation software.

Radioactive isotope production in the fast neutron nuclear reactors

The present work reviews the primary benefits of radioactive isotope production in the fast neutron reactors the accumulated foreign and local experience in usage of this type of reactors for radioactive isotope production, and also the potential new trends in development of the existing technologies. The main advantage of isotope production in the fast neutron reactors is their high capacity and lower value in general as compared with the accelerating installations. One nuclear reactor may produce dozens of different isotopes including Cj-60, Sr-89 (targets on the base of yttrium), Ni-63 (targets on the base of copper), Eu-152, Eu-154, Sm-145, Sn-117n, Cu-64 and others. It should also be emphasized that a number of radioisotopes are most efficiently produced only in fast and intermediate neutron spectra, which is not possible in nuclear thermal reactors and, above all, in research reactors. Studies have shown that the organization of large-scale production of radioisotopes can significantly increase the economic attractiveness of fast-neutron reactors.

Comparative study and TALYS 1.6 code calculations for the excitation functions of P and α-induced reactions on Bi target with special attention to the medical radioisotope 211At

The induced reactions by light ions such as protons, deuterons, 3He and α-particles on 209Bi, as the heaviest stable isotope in the periodic table, are important for the production of heavy radioactive isotopes. These radioactive isotopes are mainly α-emitters and could be used in cancer therapy. In this study, 209Bi(p,2n)208Po, 209Bi(p,3n)207Po, 209Bi(p,4n)206Po and 209Bi(p,5n)205Po reactions were studied by collecting the previously measured excitation functions, holding an inter-comparison and performing code calculations using the TALYS 1.6 code. As a result of the inter-comparison, mathematical fit for each reaction was given. α-induced reactions on 209Bi target leading to the formation of 210,211At and 210Po radioisotope were also studied through this work. The production of 211At without considerable isotopic 210At impurities was discussed. The previously measured excitation functions were fitted as before, and TALYS 1.6 code calculation was performed. The code calculations were compared with the mathematical fitted excitation functions.

Cosmogenic Activation of Germanium Detectors in EDELWEISS III

Activation of germanium crystals due to cosmic rays becomes a serious limitation for experiments searching for rare events with germanium detectors. Cosmic ray induced activation of the detector components and, even more importantly, of the germanium itself during production, transportation and storage at the Earth’s surface, might result in the production of radioactive isotopes with long half-lives, with a possible impact on the expected background. We present a measurement of the cosmogenic activation in the cryogenic germanium detectors of the EDELWEISS III direct dark matter search experiment. The decay rates measured in detectors with different exposures to cosmic rays above ground are converted into production rates of different isotopes. They are compared to model predictions present in literature and to estimates calculated with the ACTIVIA code.

Theoretical study on production of stable and radioactive isotopes from proton irradiated sodium chloride

The search for new radioactive isotopes has been on the rise due to high demands of positron-emitting radionuclides applicable for positron emission tomography (PET) modality in nuclear medicine. In this investigation, proton irradiations of sodium chloride (NaCl) were theoretically highlighted, including discussion on stable and radioactive isotopes produced during proton bombardment of the NaCl target. TALYS 2015-Calculated results indicated that 23Mg, 20Ne, 32S, 35Ar, 37Ar and 34S were expectedly produced following NaCl irradiation with 11 MeV protons. More isotopes such as 22Na, 34mCl, 36Cl and 36Ar were generated when the proton energy was increased to 26.5 MeV. Positron emitting radionuclides were found to dominate.

Parameter Assessment of Beam Transport Line for Nuclear Physics Research

The IBA CP30 cyclotron was installed at the 108 Central Hospital in Hanoi, Vietnam. A proton beam with energy range from 15 to 30 MeV can be delivered by this facility. Currently, facility is mainly used for medical radioactive isotope production. There is an idea to use this accelerator for scientific research as well. For this purpose, a new beam line should be designed. A high energy resolution with minimum momentum spread is a key point for designing. A preliminary design of the beam line using matrix codes, modeling 3D optical elements, magnetic field calculations, and beam dynamics analysis is presented in this paper.

Features of Correlated States and a Mechanism of Self-Similar Selection of Nuclear Reaction Channels Involving Low-Energy Charged Particles

Features of the Robertson–Schrodinger coordinate–momentum and energy–time uncertainty relations and connection between them have been considered. A method has been proposed to determine the duration of giant energy fluctuations of particles in a correlated coherent state. This method makes it possible to justify both a huge (many orders of magnitude) increase in the probability of the tunnel effect with the subsequent low-energy nuclear reaction and the automatic selection of low-energy reaction channels involving charged particles and the exclusion of the production of radioactive daughter isotopes. It has been shown that the same mechanism of formation of correlated coherent states explains a very significant suppression of gamma radiation observed in such reactions stimulated by the virtual energy as compared to similar reactions proceeding at a high “real” energy of particles.