Search results for "Plasma"
showing 10 items of 4043 documents
Formation of dislocations and hardening of LiF under high-dose irradiation with 5–21 MeV 12C ions
2017
R. Zabels, I. Manika, J. Maniks, and R.Grants acknowledge the national project IMIS2, and A. Dauletbekova, M. Baizhumanov, and M. Zdorovets the Ministry of Education and Science of the Republic of Kazakhstan for the financial support.
High-Power Multicarrier Generation for RF Breakdown Testing
2017
Testing of satellite components for high RF power breakdown effects, such as multipactor and corona or passive-intermodulation, is a topic of growing interest in the aerospaceindustry. Switching fromthe classical single carrier approach to the more realisticmulticarrier scenario is very challenging from the experimental point of view. Themulticarrier signals, amplifiedby several RF power amplifiers, need to have controlled phase, amplitude, and frequency in each carrier. Fine tuning of the signal generator phases is required in order to compensate the phase drift occurring in the active elements of the test bed. This paper presents an efficient and low-cost technique to generate multicarrie…
High-frequency electrodeless lamps in argon–mercury mixtures
2005
In this paper, numerical and experimental investigations of high-frequency (HF) electrodeless lamps in argon–mercury mixtures are performed. The intensities of the mercury spectral lines having wavelengths λ = 404.66, 435.83, 546.07 nm (7 3S1–6 3P0,1,2) and the resonance line λ = 253.7 nm (6 3 P1–6 1S0) are measured at a wide range of mercury pressures, varying the HF generator current and argon filling pressure. A stationary self-consistent model of HF electrodeless discharge lamp is developed including kinetics of the excited mercury and argon atomic states. Based on the developed model, the radiation characteristics of the discharge plasma are calculated. Numerical simulation of the line…
First experiments on applying the gasdynamic ECR ion source for negative hydrogen ion production
2017
This article has no abstract. peerReviewed
Injected 1+ ion beam as a diagnostics tool of charge breeder ECR ion source plasmas
2015
International audience; Charge breeder electron cyclotron resonance ion sources (CB-ECRIS) are used as 1+ →n+ charge multiplication devices of post-accelerated radioactive ion beams. The charge breeding process involves thermalization of the injected 1+ ions with the plasma ions in ion–ion collisions, subsequent ionization by electron impact and extraction of the n+ ions. Charge breeding experiments of 85Rb and 133Cs ion beams with the 14.5 GHz PHOENIX CB-ECRIS operating with oxygen gas demonstrate the plasma diagnostics capabilities of the 1+ injection method. Two populations can be distinguished in the m/q-spectrum of the extracted ion beams, the low (1+ and 2+) charge states repres…
Ionization efficiency studies with charge breeder and conventional electron cyclotron resonance ion source
2013
Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 …
Spark Plasma Sintering à partir de poudres mécaniquement activées : compréhension des transitions de phase au cours d'un frittage réactif
2007
International audience; À " basse température " (entre 400 et 600 ◦C), l'oxydation de MoSi2 entraîne sa désintégration en poudre (phénomène de " peste "). De récents travaux ont montré que l'utilisation de MoSi2 dense et nano-organisé permettrait de ralentir ce phénomène de " peste ". Le défi de produire des matériaux denses et nano-organisés peut être relevé par le frittage " flash " réactif sous champ électrique à partir des poudres mécaniquement activées (Mechanically-Activated Spark Plasma Sintering, MASPS). Le contrôle de la composition et de la microstructure du composé intermétallique MoSi2 nécessite de déterminer les paramètres du frittage SPS (température, rampe de montée en tempér…
The α and γ plasma modes in plasma-enhanced atomic layer deposition with O2-N2 capacitive discharges
2017
Two distinguishable plasma modes in the O2–N2 radio frequency capacitively coupled plasma (CCP) used in remote plasma-enhanced atomic layer deposition (PEALD) were observed. Optical emission spectroscopy and spectra interpretation with rate coefficient analysis of the relevant processes were used to connect the detected modes to the α and γ modes of the CCP discharge. To investigate the effect of the plasma modes on the PEALD film growth, ZnO and TiO2 films were deposited using both modes and compared to the films deposited using direct plasma. The growth rate, thickness uniformity, elemental composition, and crystallinity of the films were found to correlate with the deposition mode. In re…
A quartz amplifier for high-sensitivity Fourier-transform ion-cyclotron-resonance measurements with trapped ions
2019
Single-ion sensitivity is obtained in precision Penning-trap experiments devoted to light (anti)particles or ions with low mass-to-charge ratios, by adding an inductance coil to an amplifier connected to the trap, both operated at 4 K. However, single-ion sensitivity has not been reached on heavy singly or doubly charged ions. In this publication, we present a new system to reach this point, based on the use of a quartz crystal as an inductance, together with a newly developed broad-band (BB) amplifier. We detect the reduced-cyclotron frequency of 40Ca+ ions stored in a 7-tesla open-ring Penning trap. By comparing the detected electric signal obtained with the BB amplifier and the fluoresce…
Experimental evidence on photo-assisted O− ion production from Al2O3 cathode in cesium sputter negative ion source
2020
The production of negative ions in cesium sputter ion sources is generally considered to be a pure surface process. It has been recently proposed that ion pair production could explain the higher-than-expected beam currents extracted from these ion sources, therefore opening the door for laser-assisted enhancement of the negative ion yield. We have tested this hypothesis by measuring the effect of various pulsed diode lasers on the O − beam current produced from Al 2O 3 cathode of a cesium sputter ion source. It is expected that the ion pair production of O − requires populating the 5d electronic states of neutral cesium, thus implying that the process should be provoked only with specific …