Numerical simulation of hydrogen ion species in the steady-state plasma of a low-pressure ion source

Fukumasa, Osamu; Italani, R; Saeki, Setsuo

doi:10.1088/0022-3727/18/12/012

Cited by 31 publications

(22 citation statements)

References 23 publications

(8 reference statements)

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“…This means that for partially ionized plasmas, an increase in the electron temperature would suppress the dissociation of H 2 to H atoms and increase H 2 + ion formation. Therefore, the atomic ion fraction should increase with increasing electron density and decreasing electron temperature, which matches the global model and simulation done in [14] and [15]. The highest atomic ion fraction can be achieved using 13.56 MHz with a deuterium fill gas.…”

Section: Resultssupporting

confidence: 75%

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging

Wu¹,

Hurley²,

Ji³

et al. 2009

AIP Conference Proceedings

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Abstract. We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium ( 2 D( 3 T,n) 4 α) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 10 8 n/s for a 50 μA D/T ion beam current accelerated to 80 kV. The generator utilizes a RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively-coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80% can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results, such as the current density, atomic ion fraction, electron temperature, and electron density, from ion source testing will be discussed.

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Section: Resultssupporting

confidence: 75%

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging

Wu¹,

Hurley²,

Ji³

et al. 2009

AIP Conference Proceedings

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“…Fukumasa's selection of reactions, in Ref. 8 for example, is slightly different from ours since he concentrates on higher Te values (>5 eV) for which the dominating reaction by-products, for given reactants (e + H~ for example), are different. We shall consider the reaction rate a, for reaction 4 to be constant, and equal to 1.5 x 10 -9 cm 3 s-~; this is a good approximation since for ion temperatures between 0.05 and 0.5 eV, as in our case, a4 is limited to the range (1.54-0.2) x 10-9cm3s-k The other aj rates are functions of T~ and are calculated from selected cross-sections (see Table I).…”

Section: Assumptionsmentioning

confidence: 77%

Hydrogen atom yield in RF and microwave hydrogen discharges

St‐Onge

Moisan

1994

Plasma Chem Plasma Process

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The hydrogen atom yield in pure-H2 RF and microwave-sustained Using this diagnostic, it is observed that the H-atom concentration decreases when the vessel wall temperature increases, owing to the increased efficiency of atomic hydrogen recombination on the wall. To overcome this effect, the discharge tube wall is coolecl off with dimethyl polysiloxane, a low-loss dielectric liquid. It improves significantly the H-atom concentration at 2450 MHz provided the pressure is typically below a few torr and the power density is not too high.KEY WORDS: Hydrogen atoms; H2 discharges; particle balance model; actinometry; atom recombination; wall cooling; dimethyl polysiloxane; diamond. INTRODUC~ONThe last decades have seen the emergence of several chemical vapor deposition (CVD) methods for diamond synthesis. °) Diamond thin films are particularly useful in applications such as tribology, microelectronics, and optics. ~2) The most widespread CVD method operates at gas pressures in the range 1-100 torr. The driving force for the nucleation of diamond on a substrate is provided by the supersat~iration of hydrocarbon compounds in the gas phase. Apart from diamond, graphite is also likely to deposit since it is the thermodynamically stable phase of carbon under low pressure and low temperature conditions (its Gibbs free energy is lower than that of diamond).To eliminate graphite when it deposits, large quantities of an adequate etchant must be introduced in the gas phase. Ideally, this etchant should ~D6partement de Physique, Universit6 de Montreal, Montreal, Qu6bec H3C 3)7, Canada.

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“…The production and losses are separated on the right-and left-hand sides of ( 8.20) with the first term on the left-hand side specifying the wall recombination losses [129,307,317] with coefficient (T w ), i.e. the ( N 1 / t) w -term in (8.3);…”

Section: The Changes In the Concentrations Of The Ions And Hydrogen Amentioning

confidence: 99%

Travelling-wave-sustained discharges

Schlüter

Shivarova

2007

Physics Reports

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Numerical simulation of hydrogen ion species in the steady-state plasma of a low-pressure ion source

Cited by 31 publications

References 23 publications

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging

Hydrogen atom yield in RF and microwave hydrogen discharges

Travelling-wave-sustained discharges

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