Search results for "Argon"
showing 10 items of 250 documents
Hadron energy reconstruction for the ATLAS calorimetry in the framework of the non-parametrical method
2002
This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known $e/h$ ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within $\pm 1%$ of the true values and the fractional energy resolution is $[(58\pm3)% /\sqrt{E}+(2.5\pm0.3)%]\oplus (1.7\pm0.2)/E…
Operation and characterization of a windowless gas jet target in high-intensity electron beams
2021
Abstract A cryogenic supersonic gas jet target was developed for the MAGIX experiment at the high-intensity electron accelerator MESA. It will be operated as an internal, windowless target in the energy-recovering recirculation arc of the accelerator with different target gases, e.g., hydrogen, deuterium , helium, oxygen, argon, or xenon. Detailed studies have been carried out at the existing A1 multi-spectrometer facility at the electron accelerator MAMI. This paper focuses on the developed handling procedures and diagnostic tools, and on the performance of the gas jet target under beam conditions. Considering the special features of this type of target, it proves to be well suited for a n…
Charge radii of neon isotopes across the sd neutron shell
2011
We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable Ne-20, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate Ne-17 up to the…
Molecular dynamics simulation of the damage production in Al (110) surface with slow argon ions
1986
We have developed a molecular dynamics simulation program to gain more insight into the sputtering process, especially the damage produced by it. We have studied the sputtering of aluminium (110) surface with argon ions. The Morse pair potentail was used for Al−Al interaction, the Lennard-Jones potential for Ar−Ar interaction and both the Moliere potential and the universal potential of Ziegler et al. for Ar−Al interaction. An electronic friction term proportional to the particle velocities was also used. The studied incident argon ion energies and angles were 200 and 400 eV and 0° (normal), 25°, 45° and 75°, respectively. The calculated sputtering yield and the overall shape and the mean d…
In-gas-cell laser ionization studies of plutonium isotopes at IGISOL
2016
Abstract In-gas-cell resonance laser ionization has been performed on long-lived isotopes of Pu at the IGISOL facility, Jyvaskyla. This initiates a new programme of research towards high-resolution optical spectroscopy of heavy actinide elements which can be produced in sufficient quantities at research reactors and transported to facilities elsewhere. In this work a new gas cell has been constructed for fast extraction of laser-ionized elements. Samples of 238–240,242 Pu and 244 Pu have been evaporated from Ta filaments, laser ionized, mass separated and delivered to the collinear laser spectroscopy station. Here we report on the performance of the gas cell through studies of the mass spec…
Hyperfine shifts for cesium in Argon at high density
1974
An optical pumping experiment was performed to obtain precise hfs shifts for Cs in Argon. The shifts measured include a term quadratic in the densityρ and a large temperature coefficient. The coefficients of the expansionδv/v0=a ρ+bρ2 area(80 °C)=−29.8(6)x10−9(Torr−1(0°C))b(80 °C)=+11(2)x10−14(Torr−2(0 °C)).
Gas jet studies towards an optimization of the IGISOL LIST method
2011
Abstract Gas jets emitted from an ion guide have been studied as a function of nozzle type and gas cell-to-background pressure ratio in order to obtain a low divergent, uniform jet over a distance of several cm. The jet has been probed by imaging the light emitted from excited argon or helium gas atoms. For a simple exit hole or converging-diverging nozzle, the jet diameter was found to be insensitive to the nozzle shape and inlet pressure. Sonic jets with a FWHM below 6 mm were achieved with a background pressure larger than 1 mbar in the expansion chamber. The measurements are supported by the detection of radioactive 219 Rn recoils from an alpha recoil source mounted within the gas cell.…
Surface investigation of plasma HMDSO membranes post-treated by CF4/Ar plasma
2002
Fluorination treatment has been performed on polysiloxane membranes using a plasma glow discharge of a gases mixture CF4 and argon (plasma enhanced chemical vapor deposition). Atomic force microscopy, XPS analyses and contact angle measurements have been undertaken to explain the surface transformation and behavior, which strongly depend on the morphology, the composition and the hydrophilic/hydrophobic character of the plasma-polymerized initial membranes. Main result is that fluorination, which leads to hydrophobic membranes, has a more relevant effect on amorphous silica-like membranes than on polymer-like ones, according to their chemical composition whereas the plasma surface reaction …
Hydrodynamics of the cocurrent downflow of a gas and a foaming liquid through a packed bed. Part I. Estimation of the transition boundary between the…
2004
Abstract In the study the results of investigations are presented aimed at determining such values of the operating parameters for which the change of the hydrodynamic regime occurs from the gas continuous flow (GCF) to the pulsing flow (PF). Nitrogen, helium and argon were used as the gas phase while the liquid phase was formed by the aqueous solutions of the alcohols C 1 –C 4 of the concentrations which ensured the foaming of the system. Thus a wide range of physicochemical properties of the system was covered in the experiments. The present study, as well as Part II, contain a wealth of experimental data which characterise the PF through the packing for the foam-forming systems. It is de…
Unprecedented layered coordination polymers of dithiolene group 10 metals: Magnetic and electrical properties
2016
One-pot reactions between Ni(ii), Pd(ii) or Pt(ii) salts and 3,6-dichloro-1,2-benzenedithiol (HSC6H2Cl2SH) in KOH medium under argon lead to a series of bis-dithiolene coordination polymers. X-ray analysis shows the presence of a common square planar complex [M(SC6H2Cl2S)2]2- linked to potassium cations forming either a two-dimensional coordination polymer network for {[K2(μ-H2O)2(μ-thf)(thf)2][M(SC6H2Cl2S)2]}n [M = Ni (1) and Pd (2)] or a one-dimensional coordination polymer for {[K2(μ-H2O)2(thf)6][Pt(SC6H2Cl2S)2]}n (3). In 3 the coordination environment of the potassium ions may slightly change leading to the two-dimensional coordination polymer {[K2(μ-H2O)(μ-thf)2][Pt(SC6H2Cl2S)2]}n (4) …