We report here for the first time a fabrication of betavoltaic battery prototype consisting of 200 single conversion cells based on Schottky barrier diamond diodes which have been vertically stacked ...with ~24% 63Ni radioactive isotope. The maximum electrical output power of about 0.93 μW was obtained in total volume of 5 × 5 × 3.5 mm3. We used the ion-beam assisted lift-off technique to obtain conversion cells of minimal thickness comparable with the characteristic penetration length of beta-particles emitted by 63Ni isotope. The obtained value of 15 μm was limited by the mechanical strength of produced structures and process reliability. To check the performance of thin diamond based conversion cells we carried out IV-curves measurements at electron beam irradiation in SEM. We found that the sacrificial layer for the splitting of such thin conversion cell from HPHT diamond substrate did not cause a considerable degradation of device charge collection efficiency. As a result, the fabricated prototype provided the output power density of about 10 μW/cm3, that is the best known value for nuclear batteries based on 63Ni radioisotope. Moreover, the long half-life of 63Ni isotope gives the battery specific energy of about 3300 mWh/g that is an order of magnitude higher than the typical value of commercial chemical cells.
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•We successfully used ion-beam assisted lift-off technique to fabricate 15 μm thick diamond-based energy conversion cells.•The energy conversion efficiency (~5-6 %) of produced cells was limited by relatively low open-circuit voltage (~1.1 V).•For produced conversion cells the charge collection efficiency >90% was demonstrated.•Compact (~90 mm3, 0.35 g) ~1 μW nuclear battery was developed and fabricated by using of 200 cells combined with ~24% 63Ni foil.•The battery power density of 10 μW/cm3 and specific energy of 3300 mWh/g were achieved due to cell thickness decreasing.
Nonthermal effects in solids after swift heavy ion impact Medvedev, N.; Voronkov, R.; Volkov, A.E.
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
February 2024, 2024-02-00, Letnik:
547
Journal Article
Recenzirano
This contribution is a brief introduction to nonthermal effects related to modifications of the interatomic potential upon ultrafast excitation of the electronic system of solids, primarily focusing ...on the swift heavy ion track problem. We clarify the difference between the exchange of the kinetic energy of electrons (and holes) scattering on the lattice (electron–phonon coupling, “thermal effects”) and the relaxation of the nonequilibrium potential energy of a solid (“nonthermal effects”). We discuss that at different degrees of electronic excitation, the modification of the interatomic potential may result in various phase transitions without an increase of the atomic temperature, i.e., at room temperature (nonthermal melting, formation of the superionic state), or in atomic acceleration causing “nonthermal heating” of the target atoms. Examples of various theoretically predicted effects are given, supported by known experimental observations.
We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of e^{+}e^{-} pairs observed in the excited ^{8}Be^{*} nucleus decays. Because of ...its coupling to electrons, the X could be produced in the bremsstrahlung reaction e^{-}Z→e^{-}ZX by a 100 GeV e^{-} beam incident on an active target in the NA64 experiment at the CERN Super Proton Synchrotron and observed through the subsequent decay into a e^{+}e^{-} pair. With 5.4×10^{10} electrons on target, no evidence for such decays was found, allowing us to set first limits on the X-e^{-} coupling in the range 1.3×10^{-4}≲ε_{e}≲4.2×10^{-4} excluding part of the allowed parameter space. We also set new bounds on the mixing strength of photons with dark photons (A^{'}) from nonobservation of the decay A^{'}→e^{+}e^{-} of the bremsstrahlung A^{'} with a mass ≲23 MeV.
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•A facile electrospinning method is used to produce V2O5 nanofibers.•V2O5 nanofibers cathodes provide up to 357 mA h g−1 in aqueous zinc-ion batteries.•Zn2+ intercalation affects ...structure and electrochemical properties of electrodes.•The electrodes show remarkable capacity after 500 charge–discharge cycles.
Vanadium pentoxide (V2O5) has attracted significant attention in recent years as a cathode material for aqueous zinc-ion batteries (AZIBs). Its unique layered structure allows for reversible intercalation of various multivalent ions, including Zn2+.
This paper proposes a sol–gel electrospinning method for preparation of vanadium pentoxide nanofibers, followed by thermal treatment in air. The composition and structure of the obtained powders were verified by X-ray diffraction, energy-dispersive X-ray elemental analysis, and X-ray photoelectron spectroscopy, while the morphology of the samples was investigated by scanning electron microscopy. The electrochemical properties and performance of the electrode materials based on V2O5 nanofibers were studied using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy methods. V2O5 electrodes demonstrate high specific capacity (357 mA h g−1 at 0.05Ag−1) and good long-term cyclic stability.
Hybrid membranes based on polybenzimidazole PBI-O-PhT (a polymer based on 3,3′,4,4′‑tetraaminodiphenyl oxide and 3,3‑bis(p‑carboxyphenyl)phthalide) were obtained by casting with silica particles with ...the surface modified by sulfonic groups. The morphology, thermal stability, proton conductivity under various conditions, and hydrogen permeability of the obtained membranes were investigated. It was shown that modification with small amounts of silica (2–5%) increases the conductivity and practically has no influence on the gas permeability of the hybrid membranes.
•Hybrid PBI-O-PhT membranes with sulfonated silica (PBI/SiO2-S) have been prepared.•Modification with small amounts of silica (2–5%) results in the conductivity increase.•Conductivity of the PBI/SiO2-S membrane is 0.059 S/cm at 160 °C.•The conductivity mechanism in hybrid membranes is discussed.
The protection against backscattering provided by topology is a striking property. In two-dimensional insulators, a consequence of this topological protection is the ballistic nature of the ...one-dimensional helical edge states. One demonstration of ballisticity is the quantized Hall conductance. Here we provide another demonstration of ballistic transport, in the way the edge states carry a supercurrent. The system we have investigated is a micrometre-long monocrystalline bismuth nanowire with topological surfaces, that we connect to two superconducting electrodes. We have measured the relation between the Josephson current flowing through the nanowire and the superconducting phase difference at its ends, the current-phase relation. The sharp sawtooth-shaped phase-modulated current-phase relation we find demonstrates that transport occurs selectively along two ballistic edges of the nanowire. In addition, we show that a magnetic field induces 0-π transitions and ϕ
-junction behaviour, providing a way to manipulate the phase of the supercurrent-carrying edge states and generate spin supercurrents.
Parkers’ model of thermal escape implies the search of solutions of one-dimensional hydrodynamic equations for an inviscid but thermally conducting gas with a critical point and vanishing temperature ...far from the source. The properties of solutions of this model are studied for neutral mon- and diatomic gases with the viscosity index varying from 1/2 to 1. The domains of existence and uniqueness of solutions in terms of the source Jeans escape parameter and Knudsen number are established. The solutions are found to exist only in a narrow range of the critical point Jeans parameter. The lower and upper limits of this range correspond to solutions that are dominated by either heat conduction or adiabatic expansion. Thermal escape described by Parker's model occurs in two asymptotic regimes: the low-density (LD) regime, when escape is dominated by heat conduction, and the high-density (HD) regime, when escape is dominated by adiabatic expansion. Expressions for the mass and energy escape rates in these regimes are found theoretically. The comparison of results of hydrodynamic and kinetic simulations performed in identical conditions shows that Parker's model is capable of describing thermal escape only in the HD regime, providing decent agreement with the kinetic model in terms of the atmospheric structure below the exobase and the mass and energy escape rates. In the LD regime, Parker's model predicts a much faster drop in atmospheric temperature and less extended atmospheres, and can both over- and underestimate the escape rates in orders of magnitude.
•Single tRNA tracking allows kinetics studies of ongoing translation in live cells.•tRNAs bind dynamically to chloramphenicol inhibited ribosomes.•Chloramphenicol acetyl transferase efficiently ...abolish the chloramphenicol action.
Chloramphenicol is a broad-spectrum antibiotic targeting the protein synthesis machinery by binding to the bacterial ribosome. Chloramphenicol has been considered a classic general inhibitor of translation, blocking the accommodation of aa-tRNA into the A site of the large ribosomal subunit. However, recent studies suggest that this proposed mechanism is a simplification and that the effect of chloramphenicol on mRNA translation is much more dynamic. By tracking single dye-labelled elongator and initiator tRNAs in Escherichia coli cells treated with chloramphenicol, we observe the direct effect of chloramphenicol on translation kinetics. We find clear indications of slow but significant mRNA translation on drug bound ribosomes.
We report the results of a search for a new vector boson (
A
′
) decaying into two dark matter particles
χ
1
χ
2
of different mass. The heavier
χ
2
particle subsequently decays to
χ
1
and an ...off-shell Dark Photon
A
′
∗
→
e
+
e
-
. For a sufficiently large mass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in the muon anomalous magnetic moment at Fermilab. Remarkably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained re-analyzing the previous NA64 searches for an invisible decay
A
′
→
χ
χ
¯
and axion-like or pseudo-scalar particles
a
→
γ
γ
. With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for
A
′
masses from 2
m
e
up to 390 MeV and mixing parameter
ε
between
3
×
10
-
5
and
2
×
10
-
2
.
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