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To demonstrate the large potential of proton minibeam radiotherapy (pMBRT) as a new method to treat tumor diseases, a preclinical proton minibeam radiation facility was designed. It is based on a tandem Van-de-Graaff accelerator providing a 16 MeV proton beam and a 3 GHz linac post-accelerator (designs: AVO-ADAM S.A, Geneva, Switzerland and ENEA, Frascati, Italy). To enhance the transmission of the tandem beam through the post-accelerator by a factor of 3, two drift tube buncher units were designed and constructed: A brazed 5-gap structure (adapted SCDTL tank of the TOP-IMPLART project (ENEA)) and a non-brazed low budget 4-gap structure. Both are made of copper. The performance of the two differently manufactured units was evaluated using a 16 MeV tandem accelerator beam and a Q3D magnetic spectrograph. Both buncher units achieve the required summed voltage amplitude of 42 kV and amplitude stability at a power feed of less than 800 W. [ABSTRACT FROM AUTHOR]

Abstract Extensive characterization is needed to understand how the physicochemical properties of polymeric membranes are related to their transport properties and to allow optimization of membrane design. Currently, most techniques characterize the (near)-surface region of the membrane, even though its bulk obviously also plays a significant role in the final membrane performance. To achieve depth-profiles of the elemental composition of both integrally skinned asymmetric (ISA) and thin-film composite (TFC) membranes, elastic recoil detection (ERD), an ion beam analysis technique, is now introduced to the field as a potentially highly valuable tool to complement for instance XPS, EDX or RBS. The determination of the complete elemental composition, importantly also including hydrogen, as function of the membrane thickness allows to gain knowledge about its depth-heterogeneity at an impressive combination of ca. 15 nm resolution with ppm-range sensitivity. This very low detection limit additionally allows the analytical quantification of e.g. remnants from synthesis conditions. The potential as well as the pitfalls of ERD as a novel, valuable technique for membrane characterization are critically discussed and illustrated by the determination of the thickness of polyamide-based top-layers of TFC membranes. Graphical abstract fx1 Highlights • ERD is successfully applied in membrane science. • The elemental composition of integrally skinned membranes and thin-film composite membranes is determined. • Elemental depth-profiling with a resolution of 15 nm and a sensitivity in the ppm-range is achieved. • ERD is also used to detect remnants from synthesis conditions and to determine the top-layer thickness of TFC membranes. [ABSTRACT FROM AUTHOR]

Using the reaction 7Li(7Li,10C) we tried to populate states in the tetraneutron. A peak in the energy spectrum of identified 10C, which we cannot attribute to a reaction with any other of the target components, corresponds to an excitation of the 10C+4n system of 2.93 ± 0.16 MeV. Under different kinematic conditions an equivalent peak was observed. For a binding energy of the tetraneutron of −2.93 MeV a much larger width than the observed upper limit of Γ < 0.24 MeV (mainly due to experimental spread) is expected. Therefore, we favor the interpretation that this peak corresponds to 10C in the first excited state at 3.354 MeV and a tetraneutron with a binding energy of + 0.42 ± 0.16 MeV. [ABSTRACT FROM AUTHOR]

FLASH-radiotherapy may provide significant sparing of healthy tissue through ultra-high dose rates in protons, electrons, and x-rays while maintaining the tumor control. Key factors for the FLASH effect might be oxygen depletion, the immune system, and the irradiated blood volume, but none could be fully confirmed yet. Therefore, further investigations are necessary. We investigated the protective (tissue sparing) effect of FLASH in proton treatment using an in-vivo mouse ear model. The right ears of Balb/c mice were irradiated with 20 MeV protons at the ion microprobe SNAKE in Garching near Munich by using three dose rates (Conv = 0.06 Gy/s, Flash9 = 9.3 Gy/s and Flash930 = 930 Gy/s) at a total dose of 23 Gy or 33 Gy. The ear thickness, desquamation, and erythema combined in an inflammation score were measured for 180 days. The cytokines TGF-β1, TNF-α, IL1α, and IL1β were analyzed in the blood sampled in the first 4 weeks and at termination day. No differences in inflammation reactions were visible in the 23 Gy group for the different dose rates. In the 33 Gy group, the ear swelling and the inflammation score for Flash9 was reduced by (57 ± 12) % and (67 ± 17) % and for Flash930 by (40 ± 13) % and (50 ± 17) % compared to the Conv dose rate. No changes in the cytokines in the blood could be measured. However, an estimation of the irradiated blood volume demonstrates, that 100-times more blood is irradiated when using Conv compared to using Flash9 or Flash930. This indicates that blood might play a role in the underlying mechanisms in the protective effect of FLASH. [ABSTRACT FROM AUTHOR]

To perform Four Dimensional Age Momentum Correlation measurements in the near future, where one obtains the positron lifetime in coincidence with the three dimensional momentum of the electron annihilating with the positron, we have investigated the time and position resolution of two CeBr 3 scintillators (monolithic and an array of pixels) using a Photek IPD340/Q/BI/RS microchannel plate image intensifier. The microchannel plate image intensifier has an active diameter of 40 mm and a stack of two microchannel plates in chevron configuration. The monolithic CeBr 3 scintillator was cylindrically shaped with a diameter of 40 mm and a height of 5 mm. The pixelated scintillator array covered the whole active area of the microchannel plate image intensifier and the shape of each pixel was 2.5·2.5·8 mm 3 with a pixel pitch of 3.3 mm. For the monolithic setup the measured mean single time resolution was 330 ps (FWHM) at a gamma energy of 511 keV. No significant dependence on the position was detected. The position resolution at the center of the monolithic scintillator was about 2.5 mm (FWHM) at a gamma energy of 662 keV. The single time resolution of the pixelated crystal setup reached 320 ps (FWHM) in the region of the center of the active area of the microchannel plate image intensifier. The position resolution was limited by the cross-section of the pixels. The gamma energy for the pixel setup measurements was 511 keV. [ABSTRACT FROM AUTHOR]

Abstract: Molecular stopping cross section data of Al2O3, for heavy ions of 12C, 16O, 28Si, 35Cl, 79Br within the energy range of 0.01–1.0MeV/nucleon were measured. Both direct transmission and bulk analysis methods were applied. Stopping cross sections were calculated both with the SRIM and MSTAR codes. Evaluation and intercomparison of the new data with the calculated and previously measured ones are reported in this paper. [Copyright &y& Elsevier]

Zn1-xMgxO epitaxial films with Mg concentrations 0≤x≤0.3 were grown by plasma-assisted molecular beam epitaxy on a-plane sapphire substrates. Precise determination of the Mg concentration x was performed by elastic recoil detection analysis. The bandgap energy was extracted from absorption measurements with high accuracy taking electron-hole interaction and exciton-phonon complexes into account. From these results a linear relationship between bandgap energy and Mg concentration is established for x≤0.3. Due to alloy disorder, the increase of the photoluminescence emission energy with Mg concentration is less pronounced. An analysis of the lattice parameters reveals that the epitaxial films grow biaxially strained on a-plane sapphire. [ABSTRACT FROM AUTHOR]

Sputtering experiments were performed by irradiating LiF, NaCl, and RbCl crystals with various swift heavy ions like S, Ni, I, Au with energies between 60 and 210 MeV, C60 clusters between 12 and 30 MeV or Pb ions between 730 and 6040 MeV. Sputtered species are collected on arc-shaped catchers and subsequently analyzed by elastic recoil detection analysis or Rutherford backscattering analysis. The study focuses on angular distributions and total yields for LiF and covers a broad range of experimental parameters including cleaved or rough sample surfaces, ion fluence, beam incident angles, and different ion velocities leading to electronic energy loss (Se) values from 5 to 45 keV/nm. In most cases, the angular distribution has two components, a jet-like peak perpendicular to the surface sample superimposed on a broad isotropic cosine distribution whatever is the beam incident angle. The observation of the jet depends mainly on the surface flatness and angle of ion incidence. However, the jet does not appear clearly when irradiated with C60 cluster. The sputtering yield is stoichiometric and characterized by huge total yields of up to a few 105 atoms per incident ion. The yield follows a power law as function of electronic energy loss, Y follows an exponential law with Sen with n ~ 4. While the azimuthal symmetry for sputtering is observed at low ion velocity (~1 MeV/u), it seems to be lost at high velocity (>4 MeV/u). The data provide a comprehensive overview how the angular distribution and the total sputtering yield scale with the energy loss, beam incidence angle and ion velocity. Complementary experiments have been done with NaCl and RbCl targets confirming the observation made for LiF. [ABSTRACT FROM AUTHOR]

This article discusses the materials aspects involved in the successful integration of hybrid floating gate (HFG) devices for NAND applications. In HFG, a Si(n type)\metal(p type) stack replaces the standard poly-Si FG. The high work function metal helps to enlarge the program window by limiting the leakage through the high- k intergate dielectric (IGD); the use of high- k IGD enables to scale the equivalent oxide thickness (EOT) of the HFG cell. Our recent progresses in the understanding of the materials characteristics (IGD crystallinity and HFG-IGD thermal stability) that influence memory performance have allowed to demonstrate that HFG can be a solution to scale planar flash beyond the 20 nm node with the best preferable hybrid floating gate structure being a Ru-based HFG and a 3-layers IGD stack of HfAlO\Al2O3\HfAlO. Indeed, through the correct selection and combination of materials for process conditions that are relevant in flash memory fabrication flows, we will show that program windows can be suitably engineered. Finally, the materials challenges for keeping acceptable memory retention characteristics are also highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen depth profiling in a high-k gate stack structure, SiON/HfO2/SiON/Si(001) was performed by high-resolution Rutherford backscattering spectroscopy (HRBS) in combination with angle-resolved X-ray photoelectron spectroscopy (AR-XPS). The nitrogen depth profile is determined so that both the HRBS spectrum and the angular dependence of the XPS yield are reproduced. The obtained nitrogen profile is compared with the result of high-resolution elastic recoil detection (ERD) which is the most reliable technique for depth profiling of light elements. The agreement between the result of the present combination analysis and that of high-resolution ERD is fairly good, showing that the present combination analysis is a promising method for the analysis of light elements. [Copyright &y& Elsevier]

Aluminum oxide was deposited using atomic layer deposition on either a silicon oxide or a silicon nitride interface. Water vapor or ozone were used as oxidation precursors. The structural properties of these films were investigated by time-of-flight secondary-ion-mass-spectroscopy (ToF-SIMS), X-ray photoelectron spectroscopy (XPS) and elastic recoil detection (ERD). Special attention was given to contamination issues of the film and the interface, bonding conditions and temperature influence on diffusion. The results suggest that the silicon most likely diffused along grain boundaries of polycrystalline Al2O3. Carbon and hydrogen were located at the interface and furthermore hydrogen diffused out of the film to some extent due to anneal. Carbon content in the layer was reduced when using O3 as an oxidant. The formation of metallic aluminum clusters was not observed for any of the investigated process conditions. [Copyright &y& Elsevier]

Single-phase nanocrystalline hydrogen-containing titanium zirconium carbide thin films and hydrogen-containing nanocomposite thin films consisting of a nanocrystalline hydrogen-containing titanium zirconium carbide phase in combination with an amorphous hydrogen-containing carbon network, (Ti 1-x Zr x)C 1-δ :H/a-C:H, were deposited by low temperature reactive high power impulse magnetron sputtering (HiPIMS) in a methane-argon atmosphere. High power impulse magnetron sputtering offers a high degree of ionization of sputtered particles and therefore a precise control of the thin film growth. The thin film deposition in the Ti-Zr-C-H system was carried out by a combinatorial approach via the variation of both the titanium-to-zirconium ratio as well as the carbon and hydrogen content in the coatings. A single, metallic, segmented target consisting of two triangles of pure titanium and zirconium enabled the deposition of thin films with different titanium-to‑zirconium-ratio dependent of the substrate position in front of the target within one deposition process. By variation of the CH 4 reactive gas flow at a constant Argon gas flow the carbon and hydrogen content of individual thin films was precisely adjusted. During the HiPIMS process a short pulse time of 50 μs was combined with a comparably low duty cycle of 3.3% in order to ensure a high ionization. In order to investigate the chemical composition of the thin films including hydrogen content electron probe microanalysis was combined in a self-consistent way with elastic recoil detection analysis. Structural analysis was done by a combination of different techniques: Raman spectroscopy suggests metal‑carbon bonds attributable to a nanocrystalline metal carbide phase as well as the formation of an amorphous hydrogen-containing carbon network. X-ray diffraction shows fcc (Ti 1-x Zr x)C 1-δ :H grains with different sizes in all coatings. Transmission electron microscopy confirms the structure model of single phase nanocrystalline (Ti 1-x Zr x)C 1-δ :H grains embedded in a hydrogen-containing amorphous carbon matrix. Scope of this work is the low temperature deposition of the (Ti,Zr)C 1-δ :H thin films and the (Ti,Zr)C 1-δ :H/a-C:H nanocomposites by HiPIMS with precise control of the resulting chemical composition and microstructure. • (Ti 1-x Zr x)C 1-δ :H/a-C:H nanocomposites are developed by low temperature HiPIMS. • Combination of EPMA and ERD in a self-consisting way to get elemental composition. • Stable process conditions for changing from single crystal phase to nanocomposite. • Formation of a metastable single phase solid solution of (Ti 1-x Zr x)C 1-δ :H. [ABSTRACT FROM AUTHOR]

A typographical error remains in the publication of the first name of Aymann S. El-Said: Aymann should be written as Ayman. [ABSTRACT FROM AUTHOR]

Nonpolar Zn1-xMgxO epitaxial films were grown by plasma-assisted molecular beam epitaxy on a-plane ZnO substrates. A smooth surface morphology was accomplished under oxygen-rich growth conditions. The benefits of the use of ZnO substrates on the structural properties are reflected by a low-density of threading dislocations. Furthermore, no indications for the generation of basal plane stacking faults are found. The pseudomorphic growth on a-plane ZnO substrates efficiently locks the epitaxial Zn1-xMgxO films to the wurtzite structure up to x = 0.25. The Mg concentration is not constant and increases with larger thickness. The optical properties reflect the influence of alloy disorder. [ABSTRACT FROM AUTHOR]