Using a scandium neutron filter the spectrum of alpha-particles from147Sm( n, alpha) reaction at ... more Using a scandium neutron filter the spectrum of alpha-particles from147Sm( n, alpha) reaction at neutron energies around 2 keV has been measured. The partial alpha-widths averaged over the capturing compound states for two alpha-transitions have been obtained.
Measurement of the Be(n, p) cross section at thermal energy I. Tomandl,1,* J. Vacík,1 U. Köster,2... more Measurement of the Be(n, p) cross section at thermal energy I. Tomandl,1,* J. Vacík,1 U. Köster,2 L. Viererbl,3 E. A. Maugeri,4 S. Heinitz,4 D. Schumann,4 M. Ayranov,4,† J. Ballof,5 R. Catherall,5 K. Chrysalidis,5,6 T. Day Goodacre,5,7 D. Fedorov,8,5 V. Fedosseev,5 K. Johnston,5 B. Marsh,5 S. Rothe,5,7 J. Schell,5,9 and Ch. Seiffert5 1Nuclear Physics Institute, Academy of Sciences of the Czech Republic, CZ-25068 Řež, Czech Republic 2Institut Laue-Langevin, 71 av. Martyrs, F-38042 Grenoble 9, France 3Research Centre Rez, CZ-25068 Řež, Czech Republic 4Laboratory of Radiochemistry, Paul Scherrer Institut, CH-5232 Villigen, Switzerland 5ISOLDE, CERN, CH-1211 Geneva 23, Switzerland 6Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany 7School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom 8Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, 188300 Gatchina, Russia 9Institute for Materials Science and Center for Nanointegration...
In this paper, doping of porous polyethylene terephthalate membrane using Li-based solution is de... more In this paper, doping of porous polyethylene terephthalate membrane using Li-based solution is described and analyzed by nuclear analytic methods. In recent years, the polymeric porous membranes have been studied as advanced battery separators in various applications, such as portable electronic devices or electric vehicles. Apart from mechanical stability, the separators also provide electrical separation and ionic transport between the electrodes during charging and discharging processes. For application of the membranes, it is important to follow the Li distribution in the separator material over time. In this work, the distribution of Li in the porous PET foils, adepts for Li ion battery separators, was analyzed by Neutron Depth Profiling and the 3D shape of the etched pores by Ion Transmission Spectroscopy. The data obtained show that Li can be incorporated, in a passive way in the micropores in large quantities, but its amount is still limited and does not depend on time of doping. Here, the first data are presented.
ABSTRACT The following materials based on four allotrope types of nanocarbons were investigated: ... more ABSTRACT The following materials based on four allotrope types of nanocarbons were investigated: (1) fullerene C60 and hybrid C60/Ti films, (2) composites of synthetic polymers and carbon nanotubules (i.e., carbon nanohorns and carbon nanotubes), (3) graphene-based materials (films and three-dimensional scaffolds), and (4) nanocrystalline diamond-based materials (films and nanofibrous scaffolds loaded with nanodiamond particles). In general, all these substrates provided a good support for colonization with human osteoblast-like cells of the lines MG-63, Saos-2 and U-2 OS, primary osteoblasts, and also human mesenchymal stem cells (hMSC). In the case of fullerenes C60, this was true for aged, i.e., 1-year-old, films. Fresh films, i.e., 1-week-old, had a decreased number of initially adhering cells, with less spreading, growth, metabolic activity and viability, though no DNA damage was detected. In the case of C60/Ti composite films, both fresh and aged films supported cell colonization well. The improved cell performance was attributed to structural changes in fullerene molecules, such as fragmentation, oxidation and polymerization, which occur during aging or co-deposition of C60 and Ti. The addition of single-wall carbon nanohorns or multi-wall carbon nanotubes to a terpolymer of polytetrafluoroethylene, polyvinyldifluoride and polypropylene (PTFE/PVDF/PP) markedly improved the adhesion and growth of bone cells, while no significant changes in cell behavior were found on polysulfone after it had been enriched with the carbon nanotubules mentioned here. Graphene-based films and scaffolds stimulated the adhesion and osteogenic differentiation of bone-forming cells even in the absence of cell adhesion-mediating molecules and differentiation factors in the cell culture medium. Nanocrystalline diamond films proved to be excellent substrates for cell adhesion, growth and osteogenic differentiation, and this cell behavior was further improved by boron doping (concentration of 133–6700 ppm) or by oxygen termination of these films. The addition of diamond nanoparticles to nanofibrous poly(lactide-co-glycolide) (PLGA) scaffolds increased the proliferation of hMSC and supported the adhesion and growth of MG-63 cells in an extent similar to cell culture polystyrene. However, on nanofibrous poly(L-lactide) scaffolds with diamond nanoparticles, the growth of MG-63 cells decreased with increasing nanoparticle concentration.
ABSTRACT A new type of biosensors for detecting phenolic compounds is presented here. These senso... more ABSTRACT A new type of biosensors for detecting phenolic compounds is presented here. These sensors consist of thin polymer foils with laccase-clad etched nuclear tracks. The presence of suitable phenolic compounds in the sensors leads to the formation of enzymatic reaction products in the tracks, which differ in their electrical conductivities from their precursor materials. These differences correlate with the concentrations of the phenolic compounds. Corresponding calibration curves have been established for a number of compounds. The sensors thus produced are capable to cover between 5 and 9 orders of magnitude in concentration in the best case down to some picomoles. The sensor's detection sensitivity strongly depends on the specific compound. It is highest for caffeic acid and acid blue 74, followed by ABTS and ferulic acid.
We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) c... more We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) cluster ion bombardment (CIB). We found that the modified layer produced by CIB includes two sublayers with different nanostructures. The top 24-nm-thick sublayer is an agglomeration of 5-nm-sized amorphous Si nanodots (a-Si NDs). The deeper 10-nm-thick sublayer is a transient layer of disordered Si as an interface between the a-Si top sublayer and the bulk Si(100). The top a-Si sublayer and the nc-Si transient layer are formed by the local heating effect and shock wave effect, respectively, induced by the cluster ion impacts. The photoluminescence (PL) spectra of the CIB-modified Si samples revealed an emission line centered at a photon energy of 1.92 eV. The absorption spectra of the modified samples exhibit enhanced light absorption at this photon energy. The parameters of the PL line require ascribing the emission origin to the quantum-confinement-induced optical transitions in the a-Si nanodots. The core-shell structure of a-Si NDs is confirmed by detection of an additional PL line centered at 2.5 eV. Analysis of the Rutherford backscattering (RBS) and the PL spectra implies the existence of -Si--O- bonds in the nanodot outer shells, which are responsible for the additional PL line. The obtained results demonstrate the valuable potential of CIB for the controllable fabrication of Si surface nanostructures, which is attractive for optoelectronics and nanoelectronics. The obtained results elucidate the evolution of structure modification occurring in silicon due to the injection of energetic C60 cluster ions with an energy of hundreds of keV.
Radiochromic films (RCF), also called GafChromic™ films, represent a performant material for accu... more Radiochromic films (RCF), also called GafChromic™ films, represent a performant material for accurate quantitative radiation dosimetry. Their compositions allow high dose sensitivity and fewer environmental dependence, giving a good feedback to the absorbed dose value and to the active media absorption, turning color upon being irradiated. The RCF take into account their reduced response near the Bragg peak due to a high linear energy transfer (LET). HD-810 GafChromic™ films are tissue-equivalent, have easy optical readings and can be employed for ion dosimetry in radio diagnostic and therapy and for industrial applications. Such dosimeters were employed at Tandetron-Nuclear Physics Institute (Řež, Czech Republic) to study the responses of helium, proton and carbon beams, commonly employed in radiotherapy and microelectronics. The sensitivity of the detector is low enough to measure multiple-beam exposures. The induced effects by the ions in the energy range of 600 keV to 2.0 MeV were investigated in terms of optical absorbance, measured in the irradiated active region of the polymer. The employed ion dose range was between 40 Gy and 2.5 kGy. The experimental results show that the absorbance increases with the irradiation time (i.e. with the absorbed dose). The absorbance induced in the radio chromic film was measured at 673 nm, at which is observed the highest sensitivity of the films. Such data, together with the dose linearity and the dependence on the ion stopping power will be presented and discussed.
In this paper, the electronic behavior of conducting swift heavy ion track networks is studied. O... more In this paper, the electronic behavior of conducting swift heavy ion track networks is studied. On the one hand, the transient conductivity of ion tracks in metal oxides on silicon in status nascendi is exploited for this purpose, and on the other hand, conducting tracks are produced by ion irradiation of insulating membranes (either self-supported or deposited onto silicon substrates),
Commercial polyimide (PI, ?kapton') and polycarbonate (PC, ?makrofol') foils have been ... more Commercial polyimide (PI, ?kapton') and polycarbonate (PC, ?makrofol') foils have been irradiated with 135 MeV Ar5+ and 340 MeV Xe7+ ions, respectively, and subsequently boiled in a 5 mole/ltr LiCI solution for different times. The depth distributions of Li diffused into the foils suggest that the doping proceeds via regular diffusion, into both unirradiated bulk and into tracks. Low fluence irradiations appear to lead to a compaction or densification of the polymer matrix. One consequence of this is a decreasing Li uptake with increasing fluence. For higher ion fluences the Li uptakeproportional to track densitybecomes dominant. It is possible to define, to first order, a mean ?effective track radius? for the average amount of lithium taken up per track, and this can be shown to be of the order of only an Å. The diffusional behaviour of lithium suggests that tracks in 340 MeV Xe ion irradiated polyimide act as open micropores for diffusing dopants. Conversely, in 135 MeV Ar irradiated PC, the dopant may only access the primary track core by passage through nearby undisturbed polymer target. A characteristic surface effect is the eventual appearance of crater-like profiles associated with the cores of ion tracks at projectile points of entry. These may be partly due to reverse ?blow-out? (backwards sputtering) in plumes of dissociated polymeric matter.
ABSTRACT The grain size dependence of the superconducting transition, the normal state resistivit... more ABSTRACT The grain size dependence of the superconducting transition, the normal state resistivity, and the insulating behavior at high magnetic fields are studied on a series of boron-doped nanocrystalline diamond (B:NCD) thin films with different grain sizes. The systematic change of the grain size is achieved by varying the methane-to-hydrogen ratio (C/H ratio) for the growth of different B:NCD films. Even though a fixed trimethylboron- (TMB) to-methane gas ratio is supposed to induce the identical boron-doping level in all the B:NCD films, the boron concentration and the carrier density are found to be a decreasing function of the grain size. Another consequence of the increase in grain size is the decreasing grain boundary density. These two concurrent consequences of the chemical vapor deposition mode of B:NCD are responsible for the grain size dependence of the critical temperature TC, the localization radius aH at the boron site, the normal state resistivity ρnorm, the Hall mobility μH, the Ioffe-Regel product kFl, the HC2-T phase boundary, and the coherence length ξGL.
Using a scandium neutron filter the spectrum of alpha-particles from147Sm( n, alpha) reaction at ... more Using a scandium neutron filter the spectrum of alpha-particles from147Sm( n, alpha) reaction at neutron energies around 2 keV has been measured. The partial alpha-widths averaged over the capturing compound states for two alpha-transitions have been obtained.
Measurement of the Be(n, p) cross section at thermal energy I. Tomandl,1,* J. Vacík,1 U. Köster,2... more Measurement of the Be(n, p) cross section at thermal energy I. Tomandl,1,* J. Vacík,1 U. Köster,2 L. Viererbl,3 E. A. Maugeri,4 S. Heinitz,4 D. Schumann,4 M. Ayranov,4,† J. Ballof,5 R. Catherall,5 K. Chrysalidis,5,6 T. Day Goodacre,5,7 D. Fedorov,8,5 V. Fedosseev,5 K. Johnston,5 B. Marsh,5 S. Rothe,5,7 J. Schell,5,9 and Ch. Seiffert5 1Nuclear Physics Institute, Academy of Sciences of the Czech Republic, CZ-25068 Řež, Czech Republic 2Institut Laue-Langevin, 71 av. Martyrs, F-38042 Grenoble 9, France 3Research Centre Rez, CZ-25068 Řež, Czech Republic 4Laboratory of Radiochemistry, Paul Scherrer Institut, CH-5232 Villigen, Switzerland 5ISOLDE, CERN, CH-1211 Geneva 23, Switzerland 6Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany 7School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom 8Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, 188300 Gatchina, Russia 9Institute for Materials Science and Center for Nanointegration...
In this paper, doping of porous polyethylene terephthalate membrane using Li-based solution is de... more In this paper, doping of porous polyethylene terephthalate membrane using Li-based solution is described and analyzed by nuclear analytic methods. In recent years, the polymeric porous membranes have been studied as advanced battery separators in various applications, such as portable electronic devices or electric vehicles. Apart from mechanical stability, the separators also provide electrical separation and ionic transport between the electrodes during charging and discharging processes. For application of the membranes, it is important to follow the Li distribution in the separator material over time. In this work, the distribution of Li in the porous PET foils, adepts for Li ion battery separators, was analyzed by Neutron Depth Profiling and the 3D shape of the etched pores by Ion Transmission Spectroscopy. The data obtained show that Li can be incorporated, in a passive way in the micropores in large quantities, but its amount is still limited and does not depend on time of doping. Here, the first data are presented.
ABSTRACT The following materials based on four allotrope types of nanocarbons were investigated: ... more ABSTRACT The following materials based on four allotrope types of nanocarbons were investigated: (1) fullerene C60 and hybrid C60/Ti films, (2) composites of synthetic polymers and carbon nanotubules (i.e., carbon nanohorns and carbon nanotubes), (3) graphene-based materials (films and three-dimensional scaffolds), and (4) nanocrystalline diamond-based materials (films and nanofibrous scaffolds loaded with nanodiamond particles). In general, all these substrates provided a good support for colonization with human osteoblast-like cells of the lines MG-63, Saos-2 and U-2 OS, primary osteoblasts, and also human mesenchymal stem cells (hMSC). In the case of fullerenes C60, this was true for aged, i.e., 1-year-old, films. Fresh films, i.e., 1-week-old, had a decreased number of initially adhering cells, with less spreading, growth, metabolic activity and viability, though no DNA damage was detected. In the case of C60/Ti composite films, both fresh and aged films supported cell colonization well. The improved cell performance was attributed to structural changes in fullerene molecules, such as fragmentation, oxidation and polymerization, which occur during aging or co-deposition of C60 and Ti. The addition of single-wall carbon nanohorns or multi-wall carbon nanotubes to a terpolymer of polytetrafluoroethylene, polyvinyldifluoride and polypropylene (PTFE/PVDF/PP) markedly improved the adhesion and growth of bone cells, while no significant changes in cell behavior were found on polysulfone after it had been enriched with the carbon nanotubules mentioned here. Graphene-based films and scaffolds stimulated the adhesion and osteogenic differentiation of bone-forming cells even in the absence of cell adhesion-mediating molecules and differentiation factors in the cell culture medium. Nanocrystalline diamond films proved to be excellent substrates for cell adhesion, growth and osteogenic differentiation, and this cell behavior was further improved by boron doping (concentration of 133–6700 ppm) or by oxygen termination of these films. The addition of diamond nanoparticles to nanofibrous poly(lactide-co-glycolide) (PLGA) scaffolds increased the proliferation of hMSC and supported the adhesion and growth of MG-63 cells in an extent similar to cell culture polystyrene. However, on nanofibrous poly(L-lactide) scaffolds with diamond nanoparticles, the growth of MG-63 cells decreased with increasing nanoparticle concentration.
ABSTRACT A new type of biosensors for detecting phenolic compounds is presented here. These senso... more ABSTRACT A new type of biosensors for detecting phenolic compounds is presented here. These sensors consist of thin polymer foils with laccase-clad etched nuclear tracks. The presence of suitable phenolic compounds in the sensors leads to the formation of enzymatic reaction products in the tracks, which differ in their electrical conductivities from their precursor materials. These differences correlate with the concentrations of the phenolic compounds. Corresponding calibration curves have been established for a number of compounds. The sensors thus produced are capable to cover between 5 and 9 orders of magnitude in concentration in the best case down to some picomoles. The sensor's detection sensitivity strongly depends on the specific compound. It is highest for caffeic acid and acid blue 74, followed by ABTS and ferulic acid.
We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) c... more We report the creation of a functional nanostructure on a Si crystal surface by 200 keV C60(++) cluster ion bombardment (CIB). We found that the modified layer produced by CIB includes two sublayers with different nanostructures. The top 24-nm-thick sublayer is an agglomeration of 5-nm-sized amorphous Si nanodots (a-Si NDs). The deeper 10-nm-thick sublayer is a transient layer of disordered Si as an interface between the a-Si top sublayer and the bulk Si(100). The top a-Si sublayer and the nc-Si transient layer are formed by the local heating effect and shock wave effect, respectively, induced by the cluster ion impacts. The photoluminescence (PL) spectra of the CIB-modified Si samples revealed an emission line centered at a photon energy of 1.92 eV. The absorption spectra of the modified samples exhibit enhanced light absorption at this photon energy. The parameters of the PL line require ascribing the emission origin to the quantum-confinement-induced optical transitions in the a-Si nanodots. The core-shell structure of a-Si NDs is confirmed by detection of an additional PL line centered at 2.5 eV. Analysis of the Rutherford backscattering (RBS) and the PL spectra implies the existence of -Si--O- bonds in the nanodot outer shells, which are responsible for the additional PL line. The obtained results demonstrate the valuable potential of CIB for the controllable fabrication of Si surface nanostructures, which is attractive for optoelectronics and nanoelectronics. The obtained results elucidate the evolution of structure modification occurring in silicon due to the injection of energetic C60 cluster ions with an energy of hundreds of keV.
Radiochromic films (RCF), also called GafChromic™ films, represent a performant material for accu... more Radiochromic films (RCF), also called GafChromic™ films, represent a performant material for accurate quantitative radiation dosimetry. Their compositions allow high dose sensitivity and fewer environmental dependence, giving a good feedback to the absorbed dose value and to the active media absorption, turning color upon being irradiated. The RCF take into account their reduced response near the Bragg peak due to a high linear energy transfer (LET). HD-810 GafChromic™ films are tissue-equivalent, have easy optical readings and can be employed for ion dosimetry in radio diagnostic and therapy and for industrial applications. Such dosimeters were employed at Tandetron-Nuclear Physics Institute (Řež, Czech Republic) to study the responses of helium, proton and carbon beams, commonly employed in radiotherapy and microelectronics. The sensitivity of the detector is low enough to measure multiple-beam exposures. The induced effects by the ions in the energy range of 600 keV to 2.0 MeV were investigated in terms of optical absorbance, measured in the irradiated active region of the polymer. The employed ion dose range was between 40 Gy and 2.5 kGy. The experimental results show that the absorbance increases with the irradiation time (i.e. with the absorbed dose). The absorbance induced in the radio chromic film was measured at 673 nm, at which is observed the highest sensitivity of the films. Such data, together with the dose linearity and the dependence on the ion stopping power will be presented and discussed.
In this paper, the electronic behavior of conducting swift heavy ion track networks is studied. O... more In this paper, the electronic behavior of conducting swift heavy ion track networks is studied. On the one hand, the transient conductivity of ion tracks in metal oxides on silicon in status nascendi is exploited for this purpose, and on the other hand, conducting tracks are produced by ion irradiation of insulating membranes (either self-supported or deposited onto silicon substrates),
Commercial polyimide (PI, ?kapton') and polycarbonate (PC, ?makrofol') foils have been ... more Commercial polyimide (PI, ?kapton') and polycarbonate (PC, ?makrofol') foils have been irradiated with 135 MeV Ar5+ and 340 MeV Xe7+ ions, respectively, and subsequently boiled in a 5 mole/ltr LiCI solution for different times. The depth distributions of Li diffused into the foils suggest that the doping proceeds via regular diffusion, into both unirradiated bulk and into tracks. Low fluence irradiations appear to lead to a compaction or densification of the polymer matrix. One consequence of this is a decreasing Li uptake with increasing fluence. For higher ion fluences the Li uptakeproportional to track densitybecomes dominant. It is possible to define, to first order, a mean ?effective track radius? for the average amount of lithium taken up per track, and this can be shown to be of the order of only an Å. The diffusional behaviour of lithium suggests that tracks in 340 MeV Xe ion irradiated polyimide act as open micropores for diffusing dopants. Conversely, in 135 MeV Ar irradiated PC, the dopant may only access the primary track core by passage through nearby undisturbed polymer target. A characteristic surface effect is the eventual appearance of crater-like profiles associated with the cores of ion tracks at projectile points of entry. These may be partly due to reverse ?blow-out? (backwards sputtering) in plumes of dissociated polymeric matter.
ABSTRACT The grain size dependence of the superconducting transition, the normal state resistivit... more ABSTRACT The grain size dependence of the superconducting transition, the normal state resistivity, and the insulating behavior at high magnetic fields are studied on a series of boron-doped nanocrystalline diamond (B:NCD) thin films with different grain sizes. The systematic change of the grain size is achieved by varying the methane-to-hydrogen ratio (C/H ratio) for the growth of different B:NCD films. Even though a fixed trimethylboron- (TMB) to-methane gas ratio is supposed to induce the identical boron-doping level in all the B:NCD films, the boron concentration and the carrier density are found to be a decreasing function of the grain size. Another consequence of the increase in grain size is the decreasing grain boundary density. These two concurrent consequences of the chemical vapor deposition mode of B:NCD are responsible for the grain size dependence of the critical temperature TC, the localization radius aH at the boron site, the normal state resistivity ρnorm, the Hall mobility μH, the Ioffe-Regel product kFl, the HC2-T phase boundary, and the coherence length ξGL.
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Papers by J. Vacík