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Choosing a single target as a biomarker or therapeutic using radioactive probes
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Assessing doses to terrestrial wildlife at a radioactive waste disposal site: inter-comparison of modelling approaches
Abstract not provided
Focused ion beam for improved spatially-resolved mass spectrometry and analysis of radioactive materials for uranium isotopic analysis
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Influence of Radioactivity on Surface Charging and Aggregation Kinetics of Particles in the Atmosphere
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First on-line detection of radioactive fission isotopes produced by laser-accelerated protons
Abstract The on-going developments in laser acceleration of protons and light ions, as well as the production of strong bursts of neutrons and multi- $$\hbox {MeV}$$ MeV photons by secondary processes now provide a basis for novel high-flux nuclear physics experiments. While the maximum energy of protons resulting from Target Normal Sheath Acceleration is presently still limited to around $$100 \, \hbox {MeV}$$ 100 MeV , the generated proton peak flux within the short laser-accelerated bunches can already today exceed the values achievable at the most advanced conventional accelerators by orders of magnitude. This paper consists of two parts covering the scientific motivation and relevance of such experiments and a first proof-of-principle demonstration. In the presented experiment pulses of $$200 \, \hbox {J}$$ 200 J at $$\approx \, 500 \, \hbox {fs}$$ ≈ 500 fs duration from the PHELIX laser produced more than $$10^{12}$$ 10 12 protons with energies above $$15 \, \hbox {MeV}$$ 15 MeV in a bunch of sub-nanosecond duration. They were used to induce fission in foil targets made of natural uranium. To make use of the nonpareil flux, these targets have to be very close to the laser acceleration source, since the particle density within the bunch is strongly affected by Coulomb explosion and the velocity differences between ions of different energy. The main challenge for nuclear detection with high-purity germanium detectors is given by the strong electromagnetic pulse caused by the laser-matter interaction close to the laser acceleration source. This was mitigated by utilizing fast transport of the fission products by a gas flow to a carbon filter, where the $$\upgamma$$ γ -rays were registered. The identified nuclides include those that have half-lives down to $$39 \, \hbox {s}$$ 39 s . These results demonstrate the capability to produce, extract, and detect short-lived reaction products under the demanding experimental condition imposed by the high-power laser interaction. The approach promotes research towards relevant nuclear astrophysical studies at conditions currently only accessible at nuclear high energy density laser facilities.
Wet chemical synthesis of apatite-based waste forms – A novel room temperature method for the immobilization of radioactive iodine
The wet chemical synthesis of Pb 10 (VO 4 ) 6 I 2 apatite has been reported for the first time. The possibility of substituting Ca 2+ for Pb 2+ and (PO 4 ) 3- for (VO 4 ) 3- in the apatite structure has been explored.
Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles
This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Here, each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.
Toxic, radioactive, and disordered: a total scattering study of TlTcO 4
Neutron total scattering reveals that the phase transition in TlTcO 4 is driven by disordering of the Tl + 6s 2 lone pairs.
A technique for studying (n,p) reactions of astrophysical interest using radioactive beams with SECAR
The formation of nuclei in slightly proton-rich regions of the neutrino-driven wind of core-collapse supernovae could be attributed to the neutrino-p process (νp-process). As it proceeds via a sequence of (p,γ) and (n,p) reactions, it may produce elements in the range of Ni and Sn, considering adequate conditions. Recent studies identify a number of decisive (n,p) reactions that control the efficiency of the νp-process. The study of one such (n,p) reaction via the measurement of the reverse (p,n) in inverse kinematics was performed with SECAR at NSCL/FRIB. Proton-induced reaction measurements, especially at the mass region of interest, are notably difficult since the recoils have nearly identical masses as the unreacted projectiles. Such measurements are feasible with the adequate separation level achieved with SECAR, and the in-coincidence neutron detection. Adjustments of the SECAR system for the first (p,n) reaction measurement included the development of new ion beam optics, and the installation of the neutron detection system. The aforementioned developments along with a discussion on the preliminary results of the p(58Fe,n)58Co reaction measurement are presented.
Low Radioactive Techniques in SuperNEMO: Status of the Radon R and D
Radon is a well-known source of background with respect to the search for neutrinoless double beta decay (0{nu}{beta}{beta}), due to the high Q{sub {beta}} value of one of its daughter nucleus {sup 214}Bi. Radon has been observed and reduced down to 6.5 mBq/m{sup 3} in the NEMO-3 experiment which is looking for the 0{nu}{beta}{beta} process in {sup 100}Mo and in six other isotopes. The SuperNEMO project, a next-generation double beta decay experiment which will also use a tracko-calorimeter technique, has been in an R and D phase since 2006. The goal is to reach a sensitivity of T{sub 1/2}(0{nu})>10{sup 26} y corresponding to an effective Majorana neutrino mass of 0.05-0.1 eV with 100 kg of {sup 82}Se. Such a sensitivity requires in particular to improve the radon radiopurity down to 0.1 mBq/m{sup 3} in the tracking chamber.
Yield Of Radioactive Products Of Transfer Reactions Induced By {sup 6}He Ions On {sup 197}Au Target
The excitation functions and isomeric cross section ratios of Tl isotopes obtained at irradiation of {sup 197}Au by a {sup 6}He-ions beams with energies from 15 to 60 MeV are analyzed. The EMPIRE-2.18 code which takes into account the branching ratios of gamma-transitions of discrete gamma-cascade in a residual nucleus in the calculations of the cross sections of the isomeric and ground nuclear states production is used.
Digital signal processing for radioactive decay studies
The use of digital acquisition system has been instrumental in the investigation of proton and alpha emitting nuclei. Recent developments extend the sensitivity and breadth of the application. The digital signal processing capabilities, used predominately by UT/ORNL for decay studies, include digitizers with decreased dead time, increased sampling rates, and new innovative firmware. Digital techniques and these improvements are furthermore applicable to a range of detector systems. Improvements in experimental sensitivity for alpha and beta-delayed neutron emitters measurements as well as the next generation of superheavy experiments are discussed.
Radioactivity produced by a repetitive laser-driven proton beam using a shot-to-shot proton spectral measurement and a direct activation method
A proton beam driven by a repetitive high-intensity-laser is utilized to induce a {sup 7}Li(p,n) {sup 7}Be nuclear reaction. The total activity of {sup 7}Be are evaluated by two different methods. The activity obtained measuring the decay gamma-rays after 1912 shots at 1 Hz is 1.7 {+-} 0.2 Bq. This is in good agreement with 1.6 {+-} 0.2 Bq evaluated from the proton energy distribution measured using a time-offlight detector and the nuclear reaction cross-sections. We conclude that the production of activity can be monitored in real time using the time-of-flight-detector placed inside a diverging proton beam coupled with a high-speed signal processing system.
Calibration of a DSSSD detector with radioactive sources
The energy calibration of a DSSSD is carried out with the spectra produced by a {sup 207}Bi conversion electron source, a {sup 137}Cs gamma source and a {sup 239}Pu/{sup 241}Am/{sup 244}Cm triple alpha source, as well as employing a precision pulse generator in the whole dynamic range. Multiplicity and coincidence of signals in different strips for the same event are also studied.
Combination of thermal and electric properties’ measurement techniques in a single setup suitable for radioactive materials in controlled environments and based on the 3 ω approach
We have designed and developed a new experimental setup, based on the 3 Omega method, to measure thermal conductivity, heat capacity and electrical resistivity of variety of samples in a broad temperature range (2 to 600 K) and under magnetic fields up to 9 T. The validity of this method is tested by measuring various kinds of metallic (copper, platinum and constantan) and insulating (SiO 2 ) materials, which have a wide range of thermal conductivity values (1-400 Wm -1 K -1 ). We have successfully employed this technique for measuring thermal conductivity of two actinide single crystals, uranium dioxide and uranium nitride. Thus, this new experimental approach for studying nuclear materials will help to advance reactor fuel development and understanding. Here, we have also shown that this experimental setup can be adapted to Quantum Design PPMS measurement environment and/or cryocooler systems.