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The deposition of energy in large and small sensitive volumes is studied after ultrahigh energy heavy-ion irradiation. We demonstrate that the energy deposition increase effect previously reported in p-i-n diode detectors due to delta electrons occurs only in large sensitive volumes, but not in small ones, typical of advanced microelectronic devices, such as the cells of a 3-D NAND Flash memories. We attribute this effect to the trajectories of the secondary electrons. [ABSTRACT FROM AUTHOR]

Heavy-ion microbeams are employed for probing the radiation-sensitive regions in commercial silicon carbide (SiC) vertical double-diffused power (VD)-MOSFETs with micrometer accuracy. By scanning the beam spot over the die, a spatial periodicity was observed in the leakage current degradation, reflecting the striped structure of the power MOSFET investigated. Two different mechanisms were observed for degradation. At low drain bias (gate and source grounded), only the gate-oxide (at the JFET or neck region) is contributing in the ion-induced leakage current. For exposures at drain–source bias voltages higher than a specific threshold, additional higher drain leakage current is observed in the p-n junction region. This provides useful insights into the understanding of basic phenomena of single-event effects in SiC power devices. [ABSTRACT FROM AUTHOR]

Durango apatite was irradiated with energetic U ions of 2.64 GeV and Kr ions of 2.1 GeV, with and without simultaneous exposure to a pressure of 10.5 GPa. Analysis by confocal Raman spectroscopy gives evidence of vibrational changes being marginal for fluences below 5×1011 ions/cm2 but becoming dominant when increasing the fluence to 8×1012 ions/cm2. Samples irradiated with U ions experience severe strain resulting in crystal cracking and finally breakage at high fluences. These radiation effects are directly linked to the formation of amorphous tracks and the fraction of amorphized material increasing with fluence. Raman spectroscopy of pressurized irradiated samples shows small shifts of the band positions with decreasing pressure but without a significant change of the Grüneisen parameter. Compared to irradiations at ambient conditions, the Raman spectra of apatite irradiated at 10.5 GPa exhibit fewer modifications, suggesting a higher radiation stability of the lattice by the pressure applied. [ABSTRACT FROM AUTHOR]

Abstract: The results of present paper have shown that sputtering of yttrium iron garnet (Y3Fe5O12) under swift heavy ions in the electronic energy loss regime is non-stoichiometric. Here we are presenting additional experimental results for gadolinium gallium garnet (Gd3Ga5O12) as target. The irradiations were performed with different ions (50Cr (589MeV), 86Kr (195MeV) and 181Ta (400MeV)) impinging perpendicularly to the surface. As earlier, the sputtering yield was determined by collecting the emitted gadolinium and gallium atoms on a thin aluminium foil, placed upstream above the target and analyzing the Al catcher by Rutherford backscattering. Also for Gd3Ga5O12, the emission of Gd and Ga is non-stoichiometric. Sputtering appears above a critical electronic stopping power of Sth =11.6±1.5keV/nm, which is larger than the threshold for track formation, in agreement with other amorphisable materials. In addition, the angular distribution of the sputtered species was measured for Y3Fe5O12 and Gd3Ga5O12 using 200MeV Au ions impinging the surface at 20° relatively to the surface. For the two garnets the ratio of Y/Fe (and Gd/Ga) varies with the angle of emitted species and the stoichiometry seems to be preserved only for an emission perpendicular to the surface. [Copyright &y& Elsevier]

CExperimental data presented in our earlier paper [Toulemonde et al., Phys. Rev. B 85, 054112 (2012)] indicate that there are two thresholds for damage creation by swift heavy ions in CaF2. Moreover, the comparison of the track sizes observed by transmission electron microscopy and generated by different cluster and monoatomic ion beams supports the occurrence of a velocity effect in this material. [ABSTRACT FROM AUTHOR]

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yakushev, Lens, Düllmann, Khuyagbaatar, Jäger, Krier, Runke, Albers, Asai, Block, Despotopulos, Di Nitto, Eberhardt, Forsberg, Golubev, Götz, Götz, Haba, Harkness-Brennan, Herzberg, Heßberger, Hinde, Hübner, Judson, Kindler, Komori, Konki, Kratz, Kurz, Laatiaoui, Lahiri, Lommel, Maiti, Mistry, Mokry, Moody, Nagame, Omtvedt, Papadakis, Pershina, Rudolph, Samiento, Sato, Schädel, Scharrer, Schausten, Shaughnessy, Steiner, Thörle-Pospiech, Toyoshima, Trautmann, Tsukada, Uusitalo, Voss, Ward, Wegrzecki, Wiehl, Williams and Yakusheva.)

The Seebeck coefficient and electrical resistance of Bi 1-x Sb x nanowire arrays electrodeposited in etched ion-track membranes have been investigated as a function of wire diameter (40-750 nm) and composition (0 ≤ x ≤ 1). The experimental data reveal a non-monotonic dependence between thermopower and wire diameter for three different compositions. Thus, the thermopower values decrease with decreasing wire diameter, exhibiting a minimum around ∼60 nm. This non-monotonic dependence of the Seebeck coefficient is attributed to the interplay of surface and bulk states. On the one hand, the metallic properties of the surface states can contribute to decreasing the thermopower of the nanostructure with increasing surface-to-volume ratio. On the other hand, for wires thinner than ∼60 nm, the relative increase of the thermopower can be tentatively attributed to the presence of quantum-size effects on both surface and bulk states. These measurements contribute to a better understanding of the interplay between bulk and surface states in nanostructures, and indicate that the decrease of Seebeck coefficient with decreasing diameter caused by the presence of surfaces states can possibly be overcome for even thinner nanowires.

The long-term "fate" of normal human cells after single hits of charged particles is one of the oldest unsolved issues in radiation protection and cellular radiobiology. Using a high-precision heavy-ion microbeam we could target normal human fibroblasts with exactly one or five carbon ions and measured the early cytogenetic damage and the late behaviour using single-cell cloning. Around 70% of the first cycle cells presented visible aberrations in mFISH after a single ion traversal, and about 5% of the cells were still able to form colonies. In one third of selected high-proliferative colonies we observed clonal (radiation-induced) aberrations. Terminal differentiation and markers of senescence (PCNA, p16) in the descendants of cells traversed by one carbon ion occurred earlier than in controls, but no evidence of radiation-induced chromosomal instability was found. We conclude that cells surviving single-ion traversal, often carrying clonal chromosome aberrations, undergo accelerated senescence but maintain chromosomal stability.

Although capillary electrophoresis is a powerful sequencing technology, the low heat capacity of a capillary can make difficult the precise control of its temperature, particularly when the capillary is heated to reduce compressions in the separation of DNA sequencing fragments. In this paper, we demonstrate that minute oscillations in the capillary's temperature result in significant degradation in the number of theoretical plates, the resolution between adjacent peaks, and the number of bases of DNA sequence determined from the electrophoresis data. Temperature must be held stable to within 0.1 degrees C to obtain long read lengths. A Monte Carlo simulation demonstrates that this degradation is consistent with laminar flow induced by the periodic thermal expansion and contraction of the separation medium.

A five-capillary system has been developed for DNA sequencing and analysis. The post-column fluorescence detector is based on a sheath-flow cuvette. The instrument provides uniform and continuous illumination of the samples. The cuvette virtually eliminates cross-talk in the fluorescence signal between capillaries. Discrete single-photon counting avalanche photodiodes provide high efficiency light detection. The instrument has detection limits (3sigma) of 130 +/- 30 fluorescein molecules injected onto each capillary. Over 650 bases of sequence at 98.8% accuracy were generated in 100 min at 50 degrees C from M13mp18. Separation and detection of short tandem repeats proved efficient and accurate with the use of internal standards for direct comparison of migration times between capillaries.