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Nanodiamonds (NDs) are promising carriers of radionuclides in radiopharmaceuticals for the use in nuclear medicine. In this work, we investigated the influence of the properties of NDs suspensions, including the sizes of their aggregates, in aqueous solutions with different pH on their binding of medical isotopes 90Y and 177Lu and determination of conditions for fabricating promising conjugates for further in vivo studies. It was shown that sorption is influenced by the composition of the solution, which determines the properties of the NDs surface, while the forms of cations of the studied nuclides in the solution do not affect the sorption value. [ABSTRACT FROM AUTHOR]

The uptake of the radioisotopes 73As and 75Se was characterized on Fe3+-doped Pb resin (Eichrom Technologies) from pH 1 to 12. There is good uptake of arsenic and selenium over a wide pH range (~ 1 to 10) with a decrease only at high pH (~ 12). Column experiments were performed to demonstrate the separations of these elements from solutions with near neutral pH values (~ 6 to 8) with high yields and high radiopurity. These separations may be relevant for a wide variety of applications especially isotope harvesting research. [ABSTRACT FROM AUTHOR]

Radionuclide-based diagnostics and therapy require proper selection of production nuclear reaction based on knowledge of the production excitation functions and the achievable yields completed with data on the formation of possible impurities. In the present work the existing IAEA recommended cross section data database for production of therapeutic isotopes is extended to production of the 47Sc,47Ca(47Sc), 58mCo, 71As(71Ge), 71Ge, 77Br, 77Kr(77Br), 80mBr, 103Pd, 103Pd(103mRh), 103Ru(103mRh), 105Rh, 117mSn, 119Sb, 119mTe(119Sb), 134Ce, 135La, 149gTb, 161Tb, 165Er, 165Tm(165Er), 167Tm, 197mHg, 197gHg, 198gAu, and 230Pa(230U) radioisotopes. Nearly 60 nuclear reactions are presented and discussed. The new recommended cross-section data and their uncertainties for the production of these 21 radionuclides will be available on the Web page of the IAEA Nuclear Data Section at https://nds.iaea.org/radionuclides and also at the IAEA medical portal https://nds.iaea.org/medportal. [ABSTRACT FROM AUTHOR]

The package PbIso is a free and open R toolbox for commonly used calculations and plots of Pb–Pb isotope data and for generating Pb evolution models. In this paper, we review Pb isotope systematics and the calculations that are commonly used, such as model age, model source μ (238U/204Pb), time-integrated κ (232Th/238U), and initial Pb isotope ratios. These equations are implemented into R functions in the package PbIso. In addition, functions are provided for generating Pb evolution models, paleoisochrons, and isochrons. This allows users to apply calculations to their data in a straightforward way while providing transparency and flexibility of the calculations used. We have implemented some basic features of the PbIso package into an online shiny R application (see https://shereearmistead.github.io/software/pbiso), which makes it easy for users without any R experience to use these calculations with their own data and to generate plots. We have provided a case study from the Superior Province in Canada, showing how different Pb evolution models can be generated in PbIso and compared to Pb isotope data. [ABSTRACT FROM AUTHOR]

An AlGaAs/GaAs photovoltaic converter for a mock-up of an environmentally friendly radioisotope energy source of ultra-long use with a YPO4 :Eu/(238Pu) radioluminescent emitter with an extremely low content of the isotope 238Pu < 0.1 wt % was studied. The modeling of the Al0.8Ga0.2As/GaAs heterostructure for the conversion of nanowatt power levels of an optical signal has been carried out. The calculated and experimental efficiency of the mock-up with a photovoltaic converter at a radioluminescent source power of 1 nW was ~1.4%. [ABSTRACT FROM AUTHOR]

In this paper, we systematically studied half-lives of the different decay modes using various theoretical models such as the unified fission model (UFM) and the effective liquid drop model. Beta-decay half-lives were evaluated using semi-empirical formulae available in the literature. We compared half-lives of all the studied decay modes and identified shorter half-lives among the same in 2 0 5 − 2 3 3 Ac nuclei. We investigated the actinium series which is similar to the thorium series. Among these decay series, alpha-emitting isotopes show great promise for cancer treatment because of their short path length and high-energy transfer of radiation. Furthermore, we predicted the decay chains of the actinium isotopes. All the decay series of actinium ends with the formation of stable nuclei or with longer half-lives. The predicted decay series and new isotopes during the decay process are helpful in the field of medicine and radiotherapy. [ABSTRACT FROM AUTHOR]

One of the methods for obtaining 123I is the bombardment of gaseous 124Xe with protons, in which nuclear reactions of production and decay of 123Xe and 123I isotopes occur. After irradiation, the gas phase is condensed from the target into a special "decay container," in which the target isotope 123I is produced and accumulated during 123Xe decay. The amount of 123I produced in the target and deposited on its walls during the irradiation is comparable to the amount of 123I obtained in the decay container. A laboratory setup has been created and a process technology for extracting 123I from the walls of the target has been developed to increase the total yield of 123I. Organic solvents (acetone and diethyl ether) are used for this purpose. The proportion of the 123I extracted by washing off from the walls of the aluminum target is at least 84%. The loss during subsequent vacuum distillation of solvents does not exceed 5%. After vacuum distillation, the extracted 123I is dissolved in NaOH. At this stage, the efficiency of 123I washing-off with a 0.01 M NaOH solution is at least 95%. Nevertheless, even taking into account these losses, the proposed method makes it possible to additionally extract the 123I radionuclide from the target in an amount equal to or greater than the activity of the 123I produced using the existing technology. [ABSTRACT FROM AUTHOR]

Background: In order to support the ongoing research across Europe to facilitate access to novel radionuclides, the PRISMAP consortium (European medical radionuclides programme) was established to offer the broadest catalog of non-conventional radionuclides for medical and translational research. The aim of this article is to introduce readers with current status of novel radionuclides in Europe. Main body: A consortium questionnaire was disseminated through the PRISMAP consortium and user community, professional associations and preclinical/clinical end users in Europe and the current status of clinical end-users in nuclear medicine were identified. A total of 40 preclinical/clinical users institutions took part in the survey. Clinical end users currently use the following radionuclides in their studies: 177Lu, 68 Ga, 111In, 90Y, other alpha emitters, 225Ac, 64Cu and Terbium isotopes. Radionuclides that would be of interest for users within the next 2–5 years are 64Cu, Terbium radionuclide "family" and alpha emitters, such as 225Ac. Conclusions: Thanks to a questionnaire distributed by the PRISMAP consortium, the current status and needs of clinical end-users in nuclear medicine were identified. [ABSTRACT FROM AUTHOR]

The purpose of this research was to determine the isotope concentration of the actinide radioelements 238U, 232Th series, and 239Pu in biological samples (urine) using the alpha spectroscopy system. The samples were selected from the residence of high natural background radiation (HNBR) area and analyzed using chemical procedure. The separated sample was placed on a membrane filter by the sedimentation method, and it was prepared for counting with the alpha spectrometry system. The average radioactive concentrations found in these samples were as follows: 234U > 226Ra > 230Th > 228Ra > 228Th > 224Ra > 232Th > 239Pu. The average concentrations of 234U and 226Ra were much greater than the other radionuclides. [ABSTRACT FROM AUTHOR]

The irradiation of 176Yb with deuterons offers a promising pathway for the production of the theranostic radionuclide 177Lu. To optimize this process, calculations integrating deuteron transport, isotope production, and decay have been performed. In pure 176Yb, the undesired production of 174g+mLu occurs at higher deuteron energies, corresponding to a distribution slightly shallower than that of 177Lu. Hence, 174g+mLu can be effectively filtered out by employing either a low-energy deuteron beam or stacked foils. The utilization of stacked foils enables the production of 177Lu using a high-energy linear accelerator. Another unwanted isotope, 176mLu, is produced roughly at the same depth as 177Lu, but its concentration can be significantly reduced by selecting an appropriate post-irradiation processing time, owing to its relatively short half-life. The modeling approach extended to the mapping of yields as a function of irradiation time and post-irradiation processing time. An optimized processing time window was identified. The study demonstrates that a high-energy deuteron beam can be employed to produce 177Lu with high specific activity exceeding 3000 GBq/mg. The effect of different purity levels (ranging from 98% to 100%) was also discussed. The impurity levels have a slight impact. The modeling demonstrates the feasibility of obtaining 177Lu with a specific activity > 3000 GBq/mg and radionuclidic purity > 99.5% when using a commercially available 176Yb target of 99.6% purity. [ABSTRACT FROM AUTHOR]

Terbium is an element that has four isotopes with interesting properties for medical applications, 149, 152, 155, 161Tb. These radioisotopes are however far from being sufficiently accessible, thereby hindering the pursuit of research on radiolabelling as well as clinical or preclinical investigations. Their lack of market availability is explained by difficulties in producing these radioisotopes with high purity and specific activity. While 161Tb can be produced using neutron capture in nuclear reactors, for 149, 152, 155Tb, a production route involving the ISOL technique is under study within the Tb-IRMA-V project. The ongoing R&D towards the production and extraction of these isotopes from an ISOL target at the ISOL@MYRRHA facility is reported in this contribution. [ABSTRACT FROM AUTHOR]

In heavy-ion-induced projectile fragmentation reactions at Fermi energies vast amount of different nuclides far from stability line are born. These neutron or proton-reach isotopes can be used as secondary beams to obtain even more exotic new isotopes or to study nuclear interactions of halo nuclei and their radii and other yet unsolved scientific problems. Radioactive isotopes produced in fragmentation reactions can be used in medical and industrial applications. In this paper we present velocity and isotope distributions of fragments from Na to Ca obtained in the collision of Ar beam of 36.5 MeV on Be target on COMBAS mass-spectrometer at FLNR, JINR. We compare the experimental results with the calculations fulfilled in combined transport-statistical model and show good agreement between them. [ABSTRACT FROM AUTHOR]

Produced and distributed at subsidized prices by national nuclear establishments, radioisotopes provided the earliest non-military application of nuclear energy. Starting in the late 1940s, thanks to their multiple uses in medicine and research, they were ubiquitous in conceptions for peaceful nuclear programs. In the 1950s, Atoms for Peace initiatives encouraged nuclear establishments to develop industrial applications of radioisotopes, stressing the economic benefits of their use. However, the spread of radioisotopes in industry turned out to be more problematic than envisaged, as it had to confront an increasing awareness of radiation risks. In this sense, the main effect of Atoms for Peace seems to have been the establishment of the International Atomic Energy Agency (IAEA) as the major actor in dealing with isotopes and their commercial distribution. [ABSTRACT FROM AUTHOR]

In order to study the effect of air masses on the distribution of artificial radionuclides on both sides of the mountain range, Pu and 137Cs in forest soils of the Qinling Mountains in Shaanxi Province were determined for the first time. The 239+240Pu and 137Cs activity concentrations ranged from 0.001 ± 0.001 to 0.501 ± 0.031 Bq/kg and 0.27 ± 0.06 to 7.82 ± 0.34 Bq/kg, respectively. The 240Pu/239Pu atom ratios in samples ranged from 0.160 ± 0.024 to 0.218 ± 0.037 with an average value of 0.188 ± 0.014, indicated that Pu isotopes from the Qinling Mountains mainly came from global fallout. The results of this research add the 239+240Pu activity concentrations and 240Pu/239Pu atom ratio of the Qinling Mountains, the atmospheric circulation in the Qinling Mountains did not significantly affect the Pu content. Also, it provides significant data on the radioactivity of Chinese soils. [ABSTRACT FROM AUTHOR]

Cross sections for the 141Pr(α,x) 144,143,141Pm, 138mPr, 141cum,140cumNd, and 139cumCe reactions were measured by the stacked foil technique at an alpha-particle range of 60 to 20 MeV. Most of the data were obtained for the first time. Experimental data were compared with earlier research and theoretical values from the TENDL-2021 database. Thick target yields of activation products were calculated. The reaction 141Pr(α,5n)140Pm (9.2 s)→140Nd was compared with other 140Nd production routes. [ABSTRACT FROM AUTHOR]

Melts and fluids derived from subducting/subducted oceanic lithosphere contribute significantly to mantle compositional heterogeneity. Historically metasomatized lithospheric mantle modified by varying materials, especially volatile-rich slab fluids, has been understood to be crucial for the formation of giant ore deposits, thus providing potential prospective areas for mineral exploration. However, it is not straightforward to identify superimposed effects of slab melts and fluids on the sub-continental lithosphere (SCLM) that has experienced long-lived and/or multiple metasomatism. In this study, we present a novel study using Mg and K isotopes, together with radioactive isotopes on mafic post-collisional alkaline potassic rocks (PARs) with the aim of deciphering varying agents contributing to the heterogeneous metasomatism of the SCLM beneath the southeastern Tibetan Plateau. The PARs, formed at ∼36 Ma, are characterized by high abundances of large ion lithophile elements (LILE) but depleted in high field strength elements (HFSE) with high Rb/Sr ratios, indicating a phlogopite-bearing mantle source. We find that features of light Mg (δ26Mg = −0.52 to −0.25‰) and heavy K (δ41K = −0.56 to +0.08‰) isotopes observed in the PARs are largely inherited from their mantle sources with negligible effects of kinetic fractionation, fractional crystallization and crustal level processes. Our modelling reveals that the notable divergence of Sr–Nd–Pb–Mg–K isotope compositions between PAR suites in different tectonic blocks are best understood as resulting from varying contributions of slab-derived components into the overlying mantle lithosphere, including sediment-derived melts, ocean crust-derived supercritical fluids, and marine carbonates. Particularly, their high Th/U ratios and negative correlations between δ26Mg and δ41K values suggest that slab-derived supercritical fluids can dissolve and transport Mg-rich (dolomitic) carbonate into the mantle wedge. [ABSTRACT FROM AUTHOR]

Modern, ambient tritium concentrations in precipitation are lower and more temporally consistent now that they have recovered from the historic thermonuclear bomb peak of the mid-1960s. With the bomb peak no longer the overriding influence on atmospheric tritium concentrations, anthropogenic point sources, such as nuclear-generating stations (NGS), have the largest influence, though the extent and temporal variability of this influence remains uncharacterized. The lack of precipitation monitoring locations means that spatial trends in tritium concentrations in precipitation are unknown. To address this data gap, tritium concentrations in shallow modern groundwater are interpolated throughout southern Ontario (Canada), at the center of the Great Lakes Basin, and the interpolation is tested as a precipitation proxy with a statistical comparison that shows good agreement between the shallow groundwater and precipitation datasets. The shallow groundwater tritium interpolation is used to delineate the extent of NGS influence as representing 66% of the study area. Recharge timings in the subcropping bedrock aquifers of the study area are interpreted qualitatively in areas outside of NGS influence to be primarily a mix of pre-bomb and modern recharge, with no indication of peak recharge levels remaining. The influence of drift thickness on the proportion of tritium-dead versus tritium-live samples is observed spatially and confirmed by comparing data distributions. The oldest waters (pre-1953) tend to occur in subcropping bedrock aquifers underlying the thickest sediment packages. [ABSTRACT FROM AUTHOR]

Producing novel medical radionuclides in the quantities necessary for pre-clinical and clinical use requires an ion source able to handle high ion throughputs, operated efficiently, to deliver high specific activity samples. This is only possible with the understanding of how different parameters affect the ion source performance. Offline mass separators are needed to run systematic studies that would help us to derive the laws governing those ion sources. At KU Leuven, we are refurbishing the Leuven Isotope Separator, a mass separator previously used for implantations of radioisotopes in solid-state samples and Mössbauer spectroscopy. In the past couple of years, the machine has undergone significant updates and has been adapted to integrate the target ion source units used at CERN-ISOLDE. This paper discusses the modifications to the Leuven Isotope Separator, as well as its potential as a test bench for the study of radioactive ion beams in the future. [ABSTRACT FROM AUTHOR]

The article considers the possibility of producing isotopes at nuclear power plants with RBMK-1000 reactors. In particular, the specialists of NIKIET developed technical documentation for substantiating the production and expanding the range of medical isotopes at the Phase 2 power units of the Leningrad NPP. The combination of design works and calculation justification demonstrated the possibility of the safe conversion and operation of two standard channels in the RBMK-1000 control and protection system of the Leningrad NPP power units 3 and 4 for irradiating starting substances with thermal neutrons and producing 131I, 153Sm, and 177Lu. By expanding the production of medical isotopes at the Leningrad NPP, as well as at other RBMK-1000 nuclear power plants in the future, current radioisotope demand from the pharmaceutical industry can be met at the same time as enlarging the number of available preparations. [ABSTRACT FROM AUTHOR]

In this study, low-background gamma spectrometry was used to confirm the identity of a set of ordinary chondrites found in 2018 and 2019, by different expeditions, in a part of the Al-Hamada al-Hamra desert, in the region of Al-Dżabal al-Gharbi, in Libya. Ten specimens of ordinary chondrites from two different campaigns were investigated. An analysis was carried out using a unique gamma spectrometry system to obtain the optimal measurement conditions for the quantitative identification of the radioactive isotopes. Chondrite radiometric studies enabled a detailed analysis of the activities of radioactive isotopes—the short-lived 22Na, 54Mn, 60Co, and long-lived 26Al, 40K. For most isotopes, the activities are expected to be similar for ordinary chondrites with the same irradiation history. Short-lived radionuclide concentrations can be considered, as a specific fingerprint of the chondrite terrestrial age, to confirm whether meteorites originate from a single fall. The HaH 346 group of chondrites was classified in February 2021. The data sets have been analyzed based on multivariate chemometric techniques, including K-means, PCA, and clustering analysis, to derive essential information and confirm similarities or significant differences between the studied specimens. [ABSTRACT FROM AUTHOR]

Determining the origin of groundwater in active and unstable mining environments has proven quite challenging. We evaluated the origin and salinity of the groundwater using major/minor ions, 2H and 18O stable isotopes, and 3H and 14C radioisotopes. Samples were collected from a multi-aquifer system including three distinct aquifers: an upper alluvial aquifer (UAA), a lower alluvial aquifer (LAA), and a hard-rock aquifer (HRA). The water facies for most of the samples were Na-Cl with total dissolved solid concentrations ranging from 1.1 g L−1 in the freshwater of the Kheirabad aquifer (KhA), 148.8 g L−1 in the brines of the HRA, and 321 g L−1 in a salt playa. The unique ionic relationships between the ions imply the salinity mainly originates from halite dissolution. Moreover, the groundwater of HRA and LAA was altered by reverse cation exchange. Although the stable isotope data suggested a modern meteoric water source for the KhA samples, the UAA, LAA, and HRA groundwaters were significantly enriched relative to the local meteoric water line. Dating with 3H and 14C radioisotopes confirmed the characteristic differences between the aquifers with ages of 6200 (UAA), 18,000 (LAA), and 27,500 years (HRA), which ultimately supported their varied origins. Consequently, a regional conceptual flow model was developed based on the geological settings, stratigraphic evidence, hydrochemistry, and isotopic properties, which suggests that the UAA, LAA, and HRA were due to three transgressions of inland lakes 6200, 18,000, and 27,500 ago, respectively. [ABSTRACT FROM AUTHOR]

The numerical model of ionization in disc-shaped cavities that takes into account both the radioactive decay of the nuclide and the delay of the emission due to the particle-wall sticking is presented. The dependences of ionization efficiency on timescales characterizing radioactive decay and sticking are presented and discussed. Two different cavity shapes are considered. One of them is a flat disc cavity, more suitable for stable or long-lived but hard-to-ionize isotopes. The other is a compact cavity, superior for short-lived nuclides, especially those easy-to-ionize. Average times the particle stay inside the cavity have been estimated -- these times are more than an order of magnitude shorter in the case of a compact cavity. The influence of the extraction opening size on the efficiency of ionization in the flat disc cavity is discussed. It is shown that increasing this opening is an easy way to increase efficiency in the case of short-lived isotopes. The current-voltage curves calculated for both cavity configurations are presented. It is proved that the optimal extraction voltages for the compact and flat disc configurations are 0.5 kV and 2 kV, respectively. [ABSTRACT FROM AUTHOR]

The production cross sections of 163,165,166,167,168Tm in alpha-particle induced reactions on 165Ho were measured in 27–60 MeV energy range using the stacked-foil activation technique. The thick target yield of the medical isotope 167Tm is 2.22 MBq/µAh. The radioisotope 165Tm that can be used in the generator system to obtain 165Er is also produced. The measured excitation functions were compared with the data from TENDL-2019 and TENDL-2021 libraries and the previous experimental values. Various methods of 165Tm and 165Er production were compared. The reaction 165Ho(α,4n)165Tm → 165Er was considered as a potential method for the production of 165Er. [ABSTRACT FROM AUTHOR]

177Lu is used in medical research for various radiotheragnostic applications in nuclear medicine because of its various isotope properties. In this paper, we calculated the cross sections and production yields of the Lu isotope from different reactions X+176,174Lu and X+176Lu in energy levels from 0.001 to 100 MeV by using TALYS-1.96 and EMPIRE-3.2.2. Although n, d, and t reactions show an outstanding cross-section performance, α and t reactions show very impactful integral yield data. For the potential outcomes, these estimates are analyzed by comparing them to TENDL-2019 and EMPIRE-3.2.2. [ABSTRACT FROM AUTHOR]

Targeted Alpha Therapy (TAT) has shown very high potential for the treatment of cancers that were not responsive to other therapy options (e.g., β− therapy and chemotherapy). The main constraint to the widespread use of TAT in clinics is the limited availability of alpha-emitting radionuclides. One of the most promising candidates for TAT is 225Ac (t 1/2 = 9.92 days), which can be used directly in combination with selective biomolecules (e.g., antibodies, peptides, etc.) or be a generator source of 213Bi (t 1/2 = 45.6 min), another shorter-lived TAT radionuclide. Several strategies are currently under investigation to increase the supply of 225Ac. One of the most attractive options is the irradiation of natural thorium-232 targets with high-energy protons (≥100 MeV). However, there are several challenges associated with this production method including the development of an efficient radiochemical purification method. During irradiation of natural thorium with proton energy above 100 MeV, several Ra isotopes (223,224,225Ra) are produced. 223Ra (t 1/2 = 11.43 days) is used for the treatment of bone metastases and can also be used as a generator source for 211Pb. Additionally, 225Ra (t 1/2 = 14.9 days) can be a valuable source of isotopically pure 225Ac. In the present work, we address the radiochemical separation aspects of isolating Ac and Ra isotopes from irradiated thorium targets. [Display omitted] • Actinium-225 (t 1/2 = 9.92 d) is one of the most promising candidates for Targeted Alpha Therapy (TAT) • The irradiation of natural thorium with high energy protons can provide clinically relevant amounts of 225Ac/213Bi and 223Ra • Ac and Ra can be isolated from the bulk mass of Th(IV) and co-produced fission products via cation exchange chromatography in trichloacetic acid • DN Resin allows the purification of Ac from lanthanides [ABSTRACT FROM AUTHOR]

Radioactive iodine isotopes play a pivotal role in radiopharmaceuticals. Large‐scale production of multi‐patient dose of radioiodinated nuclear medicines requires high concentration of radioiodine. We demonstrate that tetrabutylammonium chloride and methyltrioctylamonium chloride are effective phase transfer reagents to concentrate iodide‐124, iodide‐125 and iodide‐131 from the corresponding commercial water solutions. The resulting concentrated radioiodide, in the presence of either phase transfer reagent, does not hamper the chemical reactivity of aqueous radioiodide in the copper (II)‐mediated one‐pot three‐component click chemistry to produce radioiodinated iodotriazoles. [ABSTRACT FROM AUTHOR]

• A significant impact of air pollution on the gamma-ray spectrum was confirmed. • 210Pb and 40K are mostly correlated with the PM concentration in the air. • A purification system for the gamma spectrometer chamber was proposed. • The effectiveness of the filtration system has been proven. • For the 46.5 keV ROI of the 210Pb isotope, the background decreased by 71 %. Gamma-ray spectrometry has wide applications in various fields of science, technology, medicine, and basic research. Despite many advantages of this technique, background quantification constitutes one of the challenges in performing measurements. This study aimed to show the effect of air pollution on gamma spectrometric measurements and provide a low-cost system to improve their quality. To improve the background parameters of the spectrometer, a special system was implemented to ventilate the detector chamber, where the air stream is cleaned using a HEPA (High Efficiency Particulate Air) filter and nitrogen evaporating from the dewar's vessel.. A strong correlation was observed between the concentrations of particulates in the air and the level of count rates in specific areas of the gamma spectrum. For example, the results show a significant effect of reductions in the average number of counts within the 46.5 keV line of the 210Pb isotope, where the background decreased by 71 %. [ABSTRACT FROM AUTHOR]

Transuranium elements such as Np, Pu and Am, are considered to be the most important radioactive elements in view of their biological toxicity and environmental impact. Concentrations of 237Np, Pu isotopes and 241Am in two sediment cores collected from Peter the Great Bay of Japan Sea were determined using radiochemical separation combined with inductively coupled plasma mass spectrometry (ICP-MS) measurement. The 239,240Pu and 241Am concentrations in all sediment samples range from 0.01 Bq/kg to 2.02 Bq/kg and from 0.01 Bq/kg to 1.11 Bq/kg, respectively, which are comparable to reported values in the investigated area. The average atomic ratios of 240Pu/239Pu (0.20 ± 0.02 and 0.21 ± 0.01) and 241Am/239+240Pu activity ratios (3.32 ± 2.76 and 0.45 ± 0.17) in the two sediment cores indicated that the sources of Pu and Am in this area are global fallout and the Pacific Proving Grounds through the movement of prevailing ocean currents, and no measurable release of Np, Pu and Am from the local K-431 nuclear submarine incident was observed. The extremely low 237Np/239Pu atomic ratios ((2.0–2.5) × 10−4) in this area are mainly attributed to the discrepancy of their different chemical behaviors in the ocean due to the relatively higher solubility of 237Np compared to particle active plutonium isotopes. It was estimated using two end members model that 23% ± 6% of transuranium radionuclides originated from the Pacific Proving Grounds tests, and the rest (ca. 77%) from global fallout. [Display omitted] • Distribution of transuranium radionuclides in the sediment cores were investigated. • The contribution of transuranium from PPG was estimated to be 23 ± 6 %. • No measurable release of transuranium from K-431 incident was observed. • 237Np/239Pu atomic ratio might be unsuitable for the source identification. [ABSTRACT FROM AUTHOR]

Production cross sections of medical radionuclides 111In, 110mIn and 109Cd were investigated in the α-particle-induced reactions on natural silver up to 50 MeV. The stacked-foil activation technique and γ-ray spectrometry were used to determine the cross sections. The excitation functions of byproducts 104g,105,106m,110mAg, 107,111mCd and 107g,108g,108m,109,110gIn were also determined. Physical yields of 111In, 110mIn and 109Cd were deduced based on the measured cross sections. • Excitation functions of alpha-induced reactions on natAg up to 50 MeV were measured. • Production cross sections of the medical isotope 111In, 110mIn and 109Cd were determined. • 104g,105,106m,110mAg, 107,111mCd and 107g,108g,108m,109,110gIn are also investigated as co-produced radioactive impurities. • Physical yields of 111In, 110mIn and 109Cd were deduced based on the measured cross sections. [ABSTRACT FROM AUTHOR]

The specific activity of terrestrial potassium, thorium, and radium as well as radiocesium isotopes in Sarajevo city was determined. From the measured γ-ray spectra, the activity concentrations were determined for 40K, 232Th, 226Ra, and 137Cs with the respective average values of 460, 39, 32, and 52 Bq kg–1. The corresponding annual effective dose indoor and outdoor values were within the maximum limit of 1 mSv year–1 given by UNSCEAR. The calculated adsorbed dose rate in air was 0.058 μGy h–1. In general, all hazard index parameters were within the criterion upper limits, implying insignificant radiation risk hazard. [ABSTRACT FROM AUTHOR]

Localizing and quantifying special nuclear materials (SNMs) is desired for effective nuclear security and robust nuclear power management. Here, we demonstrate a compact radiation imaging system based on a coded aperture that allows one to form a quantified radionuclide distribution map for small amounts of SNM. The imager is based on the active scintillating medium: cerium-doped gadolinium aluminum gallium garnet [Gd3Al2Ga3O12(Ce) or GAGG(Ce)], which even in arrayed form exhibits excellent detection efficiency and good energy resolution over a wide energy range. With a $12 \times12$ array of $4\times 4\times20$ mm3 pixels, the instrument can image, at a target-to-imager separation of 1 m, 1 g of highly enriched uranium (HEU) in 4 min, 75 g of depleted uranium (DU) within 11 min, and 100 g of uranyl nitrate hexahydrate (UNH) within 11 min. The instrument, termed EPSILON-G, can also measure the ambient dose equivalent, H*(10), for radionuclides inside the unit’s 45° field of view (FOV), allowing one to accurately reconstruct the radiation dose map inside buildings. The system provides a precise determination of the H*(10) within a short acquisition time when compared to a Geiger–Muller (GM) survey meter due to the sizable area of the GAGG(Ce) scintillator array and its high density and $Z_{\text {eff}}$. Furthermore, one can identify, in real time, by means of gamma-ray detection, the accurate locations of neutron-gamma sources, as demonstrated with mixed emitters 252Cf, 239PuBe, and 241AmLi all while maintaining a gamma-ray analytical capability. [ABSTRACT FROM AUTHOR]

Identification of isotope signatures in low-count gamma-ray spectra measured with a portable NaI detector is of great importance with concern to nuclear security and non-proliferation. Specifically, in hidden radioactive source search scenarios, where a mobile detector acquires consecutive measurements in a very small interval of time (for instance every second), the measured spectra may exhibit a low number of counts and high fluctuation. These two factors challenge the radioisotope identifier algorithm both in detection accuracy and processing time by providing a high number of spectral peaks that need to be checked against known signatures. In this article, a new smart data analytics-driven transform for enhancing isotope detection is presented. In particular, a machine learning (ML) tool, i.e., the relevance vector regression (RVR), is utilized to transform the obtained signal into a form where the isotopic peaks are resolved with higher efficiency while several spectral peaks resulting from fluctuation are removed. Initially, the transform uses the data within a step-size window as its training set—self-learning (i.e., no external datasets are used) window of RVR—and subsequently replaces the window values with the RVR outputs. The presented data analytics-based transform is tested on a set of real-world gamma-ray spectra measured with a low-resolution NaI detector. Results exhibit that the presented transform improves detection certainty as obtained by two radioisotope identifier algorithms, and concurrently reduces the number of random peaks by providing a smoothed signal with fewer spectral peaks to be checked. [ABSTRACT FROM AUTHOR]

The results of complex simulations using PIC-GEANT4 (particle-in-cell and Monte-Carlo) codes based on the generation of a high-energy electron bunch by a short laser pulse propagating in a relativistic self-trapping regime in a near-critical plasma has been applied to assess the possibility of medical isotope production and nuclear waste transmutation. It has been demonstrated that a 10 Hz 30 fs 4 J laser pulse is well suited to the production of therapeutic amounts of several standard medical radionuclides (111In, 123I, 103Pd, 62Cu, 64Cu). The use of direct electron irradiation has an advantage over the use of bremsstrahlung gamma radiation from the converter due to the simplification of the production scheme without loss of radionuclide yield. The study of the transmutation of long-lived fusion products showed low efficiency and the need for preliminary isotope separation. Achieving as little as 10% reduction in the activity of a 10 g sample requires the continuous operation of the next-generation laser system at a high repetition rate (1 MHzâ€"100 kHz) for (one to ten) years. [ABSTRACT FROM AUTHOR]

Terbium has four short-lived radioactive isotopes with mass numbers 149, 152, 155, and 161, which are promising for use in various fields of nuclear medicine, but this topic is currently at the research stage. Nowadays, the conditions for the production and recovery of these carrier free isotopes from irradiated targets, and preclinical and clinical trials of radiopharmaceuticals based on these nuclides are being actively studied. The results of the relevant reports are systematized in the presented review, which makes it possible to determine the main achievements and directions of research on terbium isotopes to date. [ABSTRACT FROM AUTHOR]

A flowing-water target was irradiated with a 150 MeV/nucleon beam of 78Kr at the National Superconducting Cyclotron Laboratory to produce 77Kr and 76Kr. Real-time gamma-imaging measurements revealed the mass transport of the krypton radioisotopes through the target-water processing, or "isotope harvesting", system. The production rates were determined to be 2.7(1) × 10–4 nuclei of 76Kr and 1.18(6) × 10–2 nuclei of 77Kr formed per incident 78Kr ion. Utilizing an off-gas processing line as part of the isotope harvesting system, a total of 7.2(1) MBq of 76Kr and 19.1(6) MBq of 77Kr were collected in cold traps. Through the decay, the daughter radionuclides 76Br and 77Br were generated and removed from the traps with an average efficiency of 77 ± 12%. Due to the differences in half-lives of 76Kr and 77Kr, it was possible to isolate a pure sample of 76Br with 99.9% radionuclidic purity. The successful collection of krypton radioisotopes to generate 76Br and 77Br demonstrates the feasibility of gas-phase isotope harvesting from irradiated accelerator cooling-water. Larger-scale collections are planned for collecting by-product radionuclides from the Facility for Rare Isotope Beams. [ABSTRACT FROM AUTHOR]

We propose an innovative way to produce both 225Ac and 227Th, two precious radioisotopes enabling promising targeted alpha therapy, in a natural thorium target bombarded with a 30–90 MeV electron beam. Bremsstrahlung photons in the target are analyzed by MCNP and in-situ photonuclear transmutation of 232Th is evaluated by using the TENDL nuclear data. In the photo-transmutation analysis, 13 nuclides including 229Th and 231Pa are modelled. Special procedures with chemical separations are also proposed to produce pure 225Ac and 227Th in separate streams. In addition, performance of the new approach is compared with conventional methods in terms of the 225Ac and 227Th yields. After a Th target is bombarded with a 500 kW electron beam for a year, yearly 225Ac yield is ~ 8.47 GBq (semi-permanently) and yearly 227Th yield is ~ 48.9 GBq over 50 years, and their yields are at least doubled in a 2-year irradiation. This work will help increase global supply of the two precious isotopes and would invariably help advance TAT-related researches and developments. [ABSTRACT FROM AUTHOR]

Technetium-99 is a radioactive waste produced primarily in nuclear reactors. It is also left as radioactive waste in hospitals, directly from 99 m Tc isomeric state. To bring down the quantity of technetium-99 radioactive waste, the nuclear reactions using photon beam is explored. The integral cross section of the reaction 99Tc (γ , γ ′) 99 m Tc has been determined using the photo-nuclear activation method. The experiment was done using bremsstrahlung photons having endpoint energies viz. 6, 9, 12, 16, and 20 MeV. 115In (γ , γ ′) 115 m In reaction has been used as a monitor reaction, for the flux normalization of the bremsstrahlung spectrum. Theoretical model calculations have been done using the nuclear reaction code Talys 1.9. Theoretical parameter values are optimized with the presently obtained data. Total cross sections are estimated and investigated the feasibility of re-utilization of the technetium-99 radioactive isotope. • Re-utilization of radio isotopes for the use in radiotherapy. • 99Tc is the long lived radio isotope, which left as radioactive waste from its metastable state. • Integral cross section measurements of photon induced nuclear reactions is explored. • Transmutation capability of 99Tc using photon beam is also examined. [ABSTRACT FROM AUTHOR]

Radium isotopes, other than 226Ra, and 227Ac are typically present at low activities in the open ocean. The analysis of these isotopes thus requires the collection of large volumes of seawater and high sensitivity, low background instruments. To obtain the required large volumes (hundreds to thousands of liters), these radionuclides are typically preconcentrated on cartridge-style filters impregnated with MnO 2 (Mn-cartridges) deployed on in-situ pumps. This technique, however, requires the determination of the extraction efficiency of the Mn-cartridges for the radionuclides of interest. For Ra isotopes, we used two methods to estimate the extraction efficiency of these Mn-cartridges at two stations on the South-West Indian Ridge in the Southern Ocean (GEOTRACES GS02). Method (1) compares the 226Ra activities recovered on the Mn-cartridges versus the activities determined in Mn-fibers, through which seawater was passed at a flow rate < 1 L min−1 to quantitatively sorb Ra (Mn-fiber method) while method (2) combines the 226Ra activities determined from two Mn-cartridges placed in series on in-situ pumps (A-B method). The second method is also applied to determine the 227Ac extraction efficiency. We find a relatively wide-range of Ra and 227Ac extraction efficiencies across the dataset (from 44.8% to 99.6% for Ra, and from 23.7% to 77.5% for 227Ac). Overall, the yield of 227Ac extraction is lower than that of Ra (mean value of 49.3 ± 19.0% for 227Ac, n = 10, mean value of 79.2 ± 10.3% for Ra, n = 13, using the Mn-fiber method; and a mean value of 63.9 ± 12.5%, n = 11 using the A-B method). Our dataset suggests that the Ra extraction efficiencies using either the A-B method or the Mn-fiber method are in relatively good agreement. Consequently, the 223Ra ex , 224Ra ex and 228Ra activities determined from the Mn-cartridges by applying the two Ra extraction yields are similar. We also show that the 227Ac extraction efficiency can be estimated from the Ra extraction efficiency allowing the use of a single Mn-cartridge. Finally, we recommend to determine the Ra and 227Ac extraction efficiencies in each individual Mn-cartridge, rather than applying a single extraction efficiency to all the Mn-cartridges, since a significant variability in the extraction efficiencies was observed between the different Mn-cartridges. • We compare methods to estimate Ra and 227Ac extraction efficiency of Mn-cartridges. • The Ra extraction efficiencies of the Mn-cartridges range from 44.8% to 99.6%. • The 227Ac extraction efficiencies are lower than those for Ra (23.7–77.5%). • The 227Ac extraction efficiency can be estimated from the Ra extraction efficiency. [ABSTRACT FROM AUTHOR]

• Soil water movement was predominantly via piston flow based on the soil tritium profile. • Line-conditioned excess (lc-excess) in deep soils were consistently negative. • Large soil water deficit under orchards could be related with huge water consumption via evapotranspiration. Exploring the groundwater recharge mechanisms in regions with thick unsaturated zones can enhance our understanding of intricate groundwater processes, especially in intensive agricultural regions such as the North China Plain (NCP). For example, to better answer the question of how deep soil water can be recharged, it is of utmost importance to illustrate the recharge mechanisms of groundwater under different land use types in the NCP. This study collected soil samples from four boreholes up to 18 m deep covering farmland and orchards with different stand ages and measured soil water content (SWC), stable and radioactive isotopes (δ18O, δ2H and 3H) of both soil water and groundwater. Results indicated that the movement of water through the deep vadose zone of soils was primarily piston flow based on a soil tritium profile. The infiltration rate was estimated to be 32.2 mm yr−1 based on the tritium peak method. The variations of soil water δ18O and line control excess (lc-excess) indicated that the orchards had lower evaporation effects and a higher precipitation offset than those in farmland soils. Furthermore, the deep soil water was replenished by intensive precipitation events (from July to September). The great soil water deficit and decreased deep drainage under pear orchards is usually closely related to huge water consumption by evapotranspiration (ET) via root uptake, which explains the increase of ET in pear orchards with increasing stand age. These findings have provided substantial insights into groundwater resource management in similar regions with limited water resources and recharge modeling for regions covered with thick unsaturated zones. [ABSTRACT FROM AUTHOR]

The nuclear isomer 178 Hfm2 enables various investigations owing to its unique properties. To study exotic nuclear reactions induced by 178 Hfm2, an isomeric target is the most effective option in terms of luminosity. However, this creates many challenges to overcome. One of the challenges is that nanogram quantities of the isomer are essential for fabricating a target. We conducted a pilot experiment to establish the method for isomer production, as the first step toward large-scale production at the Radioactive Isotope Beam Factory (RIBF), RIKEN. An α beam at 40 MeV supplied from the AVF cyclotron bombarded natural-abundance metallic Yb foils. Hf isotopes were extracted from the irradiated target by a new chemical separation method. We produced a sample containing 10 11 atoms of 178 Hfm2, paving the way to future large-scale production at the RIBF. [ABSTRACT FROM AUTHOR]

A novel combination of advanced gas-chromatography and detection systems coupled to a buffer-gas cell was characterized on-line to allow gas-phase chemical studies of accelerator-produced short-lived α -decaying mercury, francium, and astatine isotopes. These were produced in 40Ar- and 48Ca-induced nuclear fusion–evaporation reactions, subsequently isolated in the recoil separators MARS at Texas A&M University, USA, and TASCA at GSI Darmstadt, Germany, before being thermalized in a buffer-gas-stopping cell. From the latter, the nuclear reaction products were extracted into gas-phase chromatographic systems, suitable for registering α -decaying short-lived radionuclides, such as isotopes of superheavy elements. Efficiencies of 21(3)% for 204-209Fr were reached for the extraction into the optimized miniCOMPACT gas-chromatography setup, indicating that this technique enables the identification of isotopes of volatile as well as non-volatile elements. These studies guide the path towards chemical investigations of superheavy elements beyond flerovium, which are out of reach with currently used setups. [ABSTRACT FROM AUTHOR]

This work concerns study of self-absorption factor (SAF) and dose rate constants of zirconium-89 (89Zr) for the purpose of radiation protection in positron emission tomography (PET) and to compare them with those of 18F-deoxyglucose (18F-FDG). We analyzed the emitted energy spectra by 18F and 89Zr through anthropomorphic phantom and calculated the absorbed energy using Monte Carlo method. The dose rate constants for both radionuclides were estimated with 2 different fluence-to-effective dose conversion coefficients. Our estimated SAF value of 0.65 for 18F agreed with the recommendation of the American Association of Physicists in Medicine (AAPM). The SAF for 89Zr was in the range of 0.61-0.66 depending on the biodistribution. Using the fluence-to-effective dose conversion coefficients recommended jointly by the American National Standards Institute and the American Nuclear Society (ANSI/ANS), the dose rate at 1 m from the patient for 18F was 0.143 mSv-MBq-1-hr-1, which is consistent with the AAPM recommendation, while that for 89Zr was 0.154 mSv-MBq-1-hr-1. With the conversion coefficients currently recommended by the International Committee on Radiological Protection (ICRP), the dose rate estimates were lowered by 2.8% and 2.6% for 89Zr and 18F, respectively. Also, we observed that the AAPM derived dose is an overestimation near the patient, compared to our simulations, which can be explained by the biodistribution nature and the assumption of the point source. Thus, we proposed new radiation protection factors for 89Zr radionuclide. [ABSTRACT FROM AUTHOR]

With the exception of beryllium, divalent cations of every alkaline earth metal are characterized by their calcimimetic behavior. Thus, in vivo biodistribution of these cations mostly occurs in form of a massive accumulation in bone tissues, consisting of hydroxyapatite to a major extent. Apart from the lightest elements beryllium and magnesium, animal studies and human studies regarding the overall in vivo behavior were carried out by using radioisotopes of the elements calcium, strontium, barium and radium. To date, only strontium with its radioisotopes and radium gained importance for applications in nuclear medicine, mainly for pain-reducing and palliative treatment of bone metastases. In contrast, barium radioisotopes can be ascertained as useful imaging agents and possible diagnostic analogues for theranostic approaches. This review focuses on the characteristic and chemical behavior of barium compounds, possible radioactive barium isotopes for future applications in nuclear medicine and radiopharmacy as well as recent results regarding barium-131 as diagnostic match for radium isotopes used in targeted alpha therapy. [Display omitted] [ABSTRACT FROM AUTHOR]

This essay examines the International Atomic Energy Agency's (IAEA's) role in the entry of hydrological isotopic analysis techniques into the developing world. The notion of using radioisotopic tracers for hydrological study came from the initiative of individual scientists, many of whom were interested in measuring the uptake of hydrogen-bomb deposited tritium in the global environment. Their proposals to include isotope hydrology among the range of IAEA activities sparked debate in the IAEA Scientific Advisory Committee and Board of Governors. At stake was not merely the future support of the technique, but the diplomatic role of the IAEA as a provider of atomic energy to the developing world, the relationship of the IAEA to other international institutions, and the articulation of what 'peaceful uses of atomic energy' really meant. In the end, the IAEA opted to render conditional support for the landmark Global Network of Isotopes in Precipitation and undertook sponsorship of expert panels that brought together isotope specialists and hydrologists. As the essay shows, the IAEA's agenda for isotope hydrology was not only a matter of technology, linked to instrumentation and technique. As a form of policy entrepreneurship, it also gave the IAEA a new diplomatic role in the larger network of international institutions. [ABSTRACT FROM AUTHOR]

An apparatus for the rapid thermal extraction of Re radioisotopes from an irradiated tungsten target has been developed. Its operation was tested using a tungsten target pre-irradiated with deuterons on the U-150 cyclotron of the Kurchatov Institute. A description of the design of the apparatus and the principle of its operation are given. It has been shown that in one two-stage calcination–sublimation cycle, at least 89% of the Re activity from the W target can be collected on the receiving area of the collector. The apparatus can be used to isolate the 186Re isotope formed from 186W upon irradiation with protons or deuterons of cyclotron targets. [ABSTRACT FROM AUTHOR]