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Alan Howling

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Related publications (68)

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Plasma deposition in an ideal showerhead reactor: a two-dimensional analytical solution

Christoph Hollenstein, Alan Howling, Boris Legradic, Michaël Chesaux

The interplay of gas flow and depletion by plasma dissociation determines the spatial distribution of species and the deposition uniformity in a plasma source. Many plasma reactors use a gas showerhead and the design of the flow dynamics is a critical aspe ...

2012

Complex image method for RF antenna-plasma inductive coupling calculation in planar geometry. Part I: basic concepts

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne, Rémy Jacquier

The coupling between an inductive source and the plasma determines the power transfer efficiency and the reflected impedance in the primary circuit. Usually, the plasma coupling is analysed by means of a transformer equivalent circuit, where the plasma ind ...

Iop Publishing Ltd2015

Surface DBD degradation in humid air, and a hybrid surface-volume DBD for robust plasma operation at high humidity

Ivo Furno, Alan Howling, Fabio Avino, Alexandra Waskow, Lorenzo Ibba, Jia Han

Surface dielectric barrier discharge performance deteriorates in humid air, with permanent and/or reversible degradation of its components. Plasma operation in a humid environment is unavoidable when humid air or water-containing materials are treated. Exp ...

IOP Publishing Ltd2023

Electromagnetic sources of nonuniformity in large area capacitive reactors

Christoph Hollenstein, Alan Howling, Laurent Fabien Hubert Sansonnens

Theory and experiment show that two electromagnetic modes are necessary and sufficient to determine the field nonuniformity within a parallel-plate rf capacitive plasma reactor. These two modes give rise to the standing wave effect and the telegraph effect ...

2007

Resonant RF network antennas for large-area and large-volume inductively coupled plasma sources

Christoph Hollenstein, Alan Howling, Philippe Frédérique Bruno Guittienne

Large-area and large-volume radio frequency (RF) plasmas are produced by different arrangements of an elementary electrical mesh consisting of two conductors interconnected by a capacitor at each end. The obtained cylindrical and planar RF networks are res ...

Iop Publishing Ltd2013

Non-intrusive plasma diagnostics for the deposition of large area thin film silicon

Christoph Hollenstein, Alan Howling, Benjamin Strahm

Plasma diagnostics for large area, industrial RF parallel-plate reactors can be useful for process optimization and monitoring, provided that their implementation is practical and non-intrusive. For instance, Fourier transform infrared (FTIR) absorption sp ...

Elsevier2009

Fast equilibration of silane/hydrogen plasmas in large area RF capacitive reactors monitored by optical emission spectroscopy

Christoph Hollenstein, Alan Howling, Laurent Fabien Hubert Sansonnens, Benjamin Strahm

The optimal plasma parameters for plasma processing, such as deposition of microcrystalline silicon from silane and hydrogen, are generally chosen in steady-state discharge conditions. However, this steady state must be reached in a short time after plasma ...

2007

Magnetic field configurational study on a helicon-based plasma source for future neutral beam systems

Ivo Furno, Alan Howling, Riccardo Agnello, Philippe Frédérique Bruno Guittienne, Rémy Jacquier

A helicon-based plasma source is under development and exploration at CEA-IRFM to produce an efficient and dense magnetized plasma column. The final objective of this development is the extraction and acceleration of a blade-like negative ion beam in view ...

IOP PUBLISHING LTD2019

Application of the shaped electrode technique to a large area rectangular capacitively coupled plasma reactor to suppress standing wave nonuniformity

Christoph Hollenstein, Alan Howling, Laurent Fabien Hubert Sansonnens, Hannes Schmidt

The electromagnetic standing wave effect can become the main source of nonuniformity limiting the use of very high frequency in large area reactors exceeding 1 m(2) required for industrial applications. Recently, it has been proposed and shown experimental ...

2006

Implementing water recirculation in a novel portable plasma-activated water reactor enhances antimicrobial effect against Escherichia coli

Ivo Furno, Alan Howling, Fabio Avino, Rita Agus, Brayden Graham Myers, Lorenzo Ibba

The need for sustainable and reliable decontamination methods is driven by concerns regarding antibiotic resistance, as well as environmental and cost -efficiency challenges associated with traditional methods. Plasmaactivated water (PAW) holds significant ...

Elsevier Science Sa2024

Complex image method for RF antenna-plasma inductive coupling calculation in planar geometry. Part II: measurements on a resonant network

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne, Rémy Jacquier

Measurements and analysis of a radio-frequency planar antenna are presented for applications in inductively-coupled plasma processing. The network of inductive and capacitive elements exhibits high currents under resonance which are efficient for plasma ge ...

Iop Publishing Ltd2015

Plasma generation by inductive coupling with a planar resonant RF network antenna

Christoph Hollenstein, Alan Howling, Philippe Frédérique Bruno Guittienne, Sylvain Lecoultre

A planar antenna operating at 13.56MHz is presented for potential applications in plasma processing. It consists of interconnected elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna exhibits a set of ...

2012

Ion heating and flows in a high power helicon source

Ivo Furno, Alan Howling, Rémy Jacquier, Riccardo Agnello, Gennady Plyushchev

We report experimental measurements of ion temperatures and flows in a high power, linear, magnetized, helicon plasma device, the Resonant Antenna Ion Device (RAID). Parallel and perpendicular ion temperatures on the order of 0.6 eV are observed for an rf ...

Amer Inst Physics2017

Two-fluid plasma model for radial Langmuir probes as a converging nozzle with sonic choked flow, and sonic passage to supersonic flow

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

Using the Lambert function, Guittienne et al. [Phys. Plasmas 25, 093519 (2018)] derived two-fluid solutions for radial Langmuir probes in collisionless and isothermal plasma. In this Brief Communication, we point out the close analogy with classical compre ...

American Institute of Physics (AIP)2019

Resonant planar antenna as an inductive plasma source

Christoph Hollenstein, Alan Howling, Philippe Frédérique Bruno Guittienne, Sylvain Lecoultre

A resonant planar antenna as an inductive plasma source operating at 13.56 MHz inside a low pressure vacuum vessel is presented for potential plasma processing applications. Its principle consists in interconnecting elementary resonant meshes composed of i ...

2012

Cavity ring-down spectroscopy to measure negative ion density in a helicon plasma source for fusion neutral beams

Ivo Furno, Alan Howling, Gennady Plyushchev, Yanis Andrebe, Riccardo Agnello, Philippe Frédérique Bruno Guittienne, Rémy Jacquier

Cavity Ring Down Spectroscopy (CRDS) is used to measure the D- absolute density produced in the helicon plasma reactor RAID (Resonant Antenna Ion Device) at the Swiss Plasma Center. The birdcage geometry of the helicon antenna produces a homogeneous, high- ...

2018

R&D around a photoneutralizer-based NBI system (Siphore) in view of a DEMO Tokamak steady state fusion reactor

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne, Rémy Jacquier

Since the signature of the ITER treaty in 2006, a new research programme targeting the emergence of a new generation of neutral beam (NB) system for the future fusion reactor (DEMO Tokamak) has been underway between several laboratories in Europe. The spec ...

IOP Publishing Ltd2015

Helicon wave-generated plasmas for negative ion beams for fusion

Ivo Furno, Alan Howling, Gennady Plyushchev, Riccardo Agnello, Philippe Frédérique Bruno Guittienne, Rémy Jacquier, Claudio Marini

In the next generation of fusion reactors, such as DEMO, neutral beam injectors (NBIs) of high energy (0.8-1 MeV) deuterium atom swith high wall-plug efficiency (>50%) will be required to reach burning plasma conditions and to provide a significant amount ...

2017

Resonant network antennas for radio-frequency plasma sources: Theory, technology and applications

Ivo Furno, Alan Howling, Philippe Frédérique Bruno Guittienne

Resonant antennas are increasingly employed by the plasma industry, and the theory has now developed alongside the technological applications to the extent that it is timely to document the progress in this field to aid antenna design for future novel RF p ...

Institute of Physics Publishing2024

Electromagnetic field nonuniformities in large area, high-frequency capacitive plasma reactors, including electrode asymmetry effects

Christoph Hollenstein, Alan Howling, Laurent Fabien Hubert Sansonnens

Electromagnetic wave propagation effects can give rise to important limitations for processing uniformity in large area, radio-frequency (rf) capacitive plasma reactors. The electromagnetic wavefield solution is derived for a capacitive, high-frequency, cy ...

2006