Al Foil Thickness Research Articles

Design and implementation of an ion beam energy degrader for use in the study of nuclear materials

A new design for an ion beam energy degrader has been developed and tested at the Reactor Materials Testing Laboratory at Queen's University. With the use of a dual rack multi-foil system, it is now possible to implant helium uniformly throughout a nickel target to a depth of 33 µm with helium ions. Aluminium foils are used in the degrader with thicknesses ranging from 2–84 µm, causing deceleration of the incident particle and thus a shallower penetration depth in the target with increased Al foil thickness. The design was successfully tested with the helium implantation of nickel superalloy, Inconel X-750. Using transmission electron microscopy, helium bubbles were imaged following an implantation of 8000 appm helium. A continuous formation of helium bubbles was observed with implantation depth, matching the predicted implantation range. The prediction for helium implantation using the aluminium foils to degrade the incident particle is carried out with data generated from SRIM calculations and an inhouse optimization code.

Slowing down of 100 keV antiprotons in Al foils

Abstract Using energy degrading foils to slow down antiprotons is of interest for producing antihydrogen atoms. I consider here the slowing down of 100 keV antiprotons, that will be produced in the ELENA storage ring under construction at CERN, to energies below 10 keV. At these low energies, they are suitable for efficient antihydrogen production. I simulate the antihydrogen motion and slowing down in Al foils using a recently developed molecular dynamics approach. The results show that the optimal Al foil thickness for slowing down the antiprotons to below 5 keV is 910 nm, and to below 10 keV is 840 nm. Also the lateral spreading of the transmitted antiprotons is reported and the uncertainties discussed.

Fabricating Al2O3-nanopores array by an ultrahigh voltage two-step anodization technique: Investigating the effect of voltage rate and Al foil thickness on geometry and ordering of the array

A densely-packed hexagonal Al2O3 nanopores array was fabricated by using a relatively simple ultrahigh voltage two-step anodization method. The developed method was technologically simple and suitable for controlling the morphology and geometry of the nanopores array as a nanodevice which has specific applications in constructing biosensors. The anodization was carried out at different applied voltage rates and Al foil thicknesses. By increasing voltage, the current density showed a peak shape profile so that its maximum was directly depended on the rate of the applied voltage. The simulation curves evidenced direct dependency of the ordering of the nanopores to the anodization voltage rate. The most ordered array was achieved at an applied voltage rate of 0.600 Vs−1 when a 1.0-mm thick Al foil was used. Spontaneous oscillation patterns (self -oscillations) were appeared at the voltage rates of 0.300, 0.400 and 0.500 Vs−1 when a 0.25-mm thick Al foil was utilized. The cross-sectional SEM images revealed that a three-dimensional periodic modulation, along the interior surfaces of the nanopores has been developed.

The impact of plasma interference profile (PIP) on argon discharge in plasma focus device

Radiation emission in a low energy (2.2 kJ, 12 kV) UM plasma focus is studied. The system is operated in Argon filling gas. Enrichment of the radiation emission yield is obtained with an optimized pressure 1.7 mbar. Time resolved radiation emission measurements are made by using an array of PIN diode detectors covered with few Al foil thicknesses, to be found at top arrangement at distance 43.50 cm from the edged-surface of hollow anode (18 cm length/1.9 cm diameter). A notable increase of radiation yield is achieved at 1.7 mbar, which is about 0.00253 mJ with efficiency of 0.00012%, and also a pragmatic consequence of ionized gas particles so-called plasma interference profile impact on the radiation emission taken as a whole. The findings may exceedingly take part in a foundation of potential applications of the electron beam emission from plasma focus (PF) device. Key words: Dense plasma focus, UM plasma focus, radiation emission, x-ray yields, argon plasma, electron beam, plasma interference profile (PIP).

Theoretical Interpretation of Atomic Charge Exchange between Singly Charged Helium Ions and Aluminum Foils

An experimental method for determining the equilibrium charge state of fast helium ions backscattered by solid Al-foils has been conducted using single Silicon Surface Barrier Detector (SBD) in a post acceleration system (PAS). The charge state measurements have been conducted to cover a wide energy range of the incident singly charged helium ion He+. The detected charge states increases from 0 to +Z with the incident ion's velocity. The method consists of measuring the charge states of ions after backscattering from the Al-foil as a function of projectile velocity and also finding the charge state distributions as a function of Al-foil thickness. The measurements are conducted for two types of Al-foil, one of which is thinner (2.5, 4.0, 5.4 ?g/cm2) and the other of which is of the order of an equilibrium foil thickness, where thicknesses of 6.8, 8.1, 9.5, and 10.8 were used. Ratios of equilibrium charge state yields for singly to doubly ionized He ions; He+1 and He+2, were also measured. The kinematics behavior of the measured He0, He+ and He+2 fractions is understood by the well-known Rutherford Backscattering Spectrometry technique (RBS). It has been shown that the dominant processes occurring to a fast He+ ions traversing Al-foil are the capture of the electron from the Al-atom to vacant state in the ion and the stripping of the bound electron from the He+ ion. The charge composition of the ion beams changes when it backscatters Al-foil, which thick enough for multiple atomic collisions, leading eventually to an equilibrium charge state distribution (ECSD). It was found that the theoretical calculations for electron-capture and loss ratios, based of semi-classical approach of Bianconi, are successful in describing the measured He ions. The satisfactory fits of the measured equilibrium charge state fractions (ECSF's) are mainly accounted to the contribution of both free valance electrons of the target and screened target nucleus in the calculation of total electron-loss cross sections. Bianconi approach is also applied to describe the measured mean equilibrium charges (MEC). The agreement between experiment and theory in this investigation is accounted to the reliability of the used post-acceleration system where all the backscattering charge-states, at certain incident ion's velocity, are separated and collected in one measurement.

Study of ${\rm Nb}_{3}{\rm Al}$ Wires for High-Field Accelerator Magnet Applications

Rapid heating, quenching and transformation (RHQT)-processed Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires possess better strain tolerance than Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires. However, RHQT-processed Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires so far developed show lower non-copper critical current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ) than recently developed high-J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires in the field range of 12-15 T. Therefore, the development of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al wires having enhancing J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> in this field range is a major concern for accelerator magnet designers. Among a number of fabrication parameters that might affect J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> properties, we analysed the effect of thickness of Al and Nb foils in the jelly-roll-shaped filaments embedded in the precursor wires. Mechanical and superconducting properties of these wires with various Al-foil thicknesses in the filaments were investigated.

Fabrication of Multiple Slit Using Stacked-Sliced Method for Hard X-ray Talbot–Lau Interferometer

We propose using a multiple slit fabricated by a simple and economical stacked-sliced method for X-ray phase imaging with a Talbot–Lau X-ray interferometer. Foils of Ta and Al were stacked alternately, and the stack was sliced up perpendicular to the stacking direction. We successfully fabricated a hard X-ray multiple slit with a space size (Al foil thickness) of about 10 µm and an aspect ratio of 60. Optical microscopy evaluation showed its regular pitch pattern at its surface. A high-resolution X-ray transmission image proved the regularity of the inner part. The visibility of moiré fringes and the phase-contrast image obtained using the Talbot–Lau interferometer with the multiple slit proved the feasibility of the stacked-sliced approach.

Analysis of 4He implanted in Al foils using the 4He(p,p) 4He backscattering interaction

Solid 4He targets were prepared by implantation of He ions of various energies into thin and thick Al host foils. He concentrations and implantation profiles were analyzed through the proton backscattering technique taking advantage of the 4He(p,p) 4He strong resonance around 2.2 MeV incident energy. The He retention was found to depend strongly on the Al foil thickness, but on the other hand it was found very stable versus the time after implantation. The consistency of the SIMNRA code was tested in different situations.

Combustion reaction in multilayered nickel and aluminum foils

Ni/Al (3/1) multilayer reaction piles were heated in a vacuum furnace and the temperature (100 readings per s for a precision of 0.2°C) of the reaction pile was measured continuously during the combustion reaction. The ignition temperature (at which the combustion starts) is almost the same independent of heating rate and the thickness of the foils. This temperature corresponds to the melting of Al which triggers the reaction. For thin Ni foils, less than 25 μm thick, the maximum temperature shows a plateau with time, close to the adiabatic reaction temperature or the eutectic temperature close to Ni3Al. For thicker Ni foils, the maximum temperature decreases with the increase of foil thickness and the combustion is incomplete. The reaction time between the ignition temperature and the maximum temperature (or the beginning of the plateau temperature) increases from 8 s for a 12.5 μm Ni foil to 125 s for a 150 μm Ni foil and the relation is almost linear. For Ni foils less than 25 μm thick, the final microstructure is homogeneous with a grain size approximately equal to the combined initial Ni and Al foil thicknesses. In the range used, 1–100°C min−1, the heating rate has very little effect on the combustion reaction. From the temperature-time profile and microstructure analysis, there are evidences of melting of Al, decomposition of Al3Ni and Al3Ni2, and the formation of NiAl and Ni3Al.