Publications associées à Klystron

Impact of beam-coupling impedance on the Schottky spectrum of bunched beam

Tatiana Pieloni, Nicolas Frank Mounet, Christophe Emmanuel R. Lannoy

The Schottky monitors of the Large Hadron Collider (LHC) can be used for non-invasive beam diagnostics to estimate various bunch characteristics, such as tune, chromaticity, bunch profile or synchrotron frequency distribution. However, collective effects, ...

Iop Publishing Ltd2024

Homogenous power distribution along gyrotron collector walls

Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Ugo Siravo, Jérémie Dubray, Miguel Filipe Silva Füglister, Pierre-François Isoz

EC RF power sources will play a major role in the future operation of large scale tokamaks (ITER, DEMO). A 1MW/170GHz gyrotron is the standard RF power unit considered for ITER. Even though the efficiency of such devices has been significantly increased th ...

2023

Toward a brightness upgrade to the SwissFEL: A high gradient traveling-wave rf photogun

Mike Seidel, Sven Reiche, Paolo Craievich, Anastasiya Magazinik

The first generation of S-band injectors for free-electron lasers has illustrated high reliability and performance by driving the latest generation of high brightness machines. However, the ultimate electron beam brightness of these devices is limited by t ...

Amer Physical Soc2023

Characterisation of electron cyclotron wall conditioning plasma in ASDEX Upgrade

Richard Pitts

Electron cyclotron wall condition (ECWC) discharges are characterised in ASDEX Upgrade with full tungsten plasma facing components and X2 polarised waves launched from the equatorial ports, relevant to ECWC conditions in ITER Pre-Fusion Power Operation pha ...

IOP Publishing Ltd2023

Emittance growth suppression with a multibunch feedback in high-energy hadron colliders: Numerical optimization of the gain and bandwidth

Xavier Buffat, Sondre Vik Furuseth

A transverse feedback system can effectively mitigate the emittance growth caused by injection oscillations and machine noise in hadron beams. However, as its action on the beam depends on beam position measurements of finite accuracy, it introduces additi ...

2021

The high-power helicon program at DIII-D: gearing up for first experiments

Alessandro Marinoni

Helicon current drive (CD), also called fast wave CD in the lower hybrid range of frequencies, has long been regarded as a promising CD tool for reactor grade plasmas. A newly installed MW-level system at DIII-D will be the first test of this technology in ...

IOP Publishing Ltd2021

Prototype mitre bends of the ex-vessel waveguide system for the ITER upper launcher: Thermal hydraulic simulations and experiments with off-center mm-wave beams

Timothy Goodman, René Chavan, Matteo Vagnoni, Anastasia Xydou, Humberto Torreblanca Quiroz

On ITER, long pulse gyrotrons are required as a power source for electron cyclotron heating (ECH) and current drive (CD). The microwaves are guided from the gyrotrons, which are placed far from the Tokamak, into the plasma by transmission lines (TLs) and a ...

2021

Linear studies of spurious backward-wave instabilities in a dielectric-loaded smooth-wall gyrotron beam ducts

Stefano Alberti, Jean-Philippe Hogge, Jérémy Genoud

Recently developed self-consistent models for beam-wave interaction simulations of a gyrotron oscillator have been extended to study spurious backward-wave instabilities in smooth-wall circular symmetric beam ducts. Starting from a purely metallic case, th ...

IEEE2020

Aqueous effluent treatment system

Jeremy Luterbacher, Gaël Peng, Frédéric Edouard Juillard, Lionel Bertschy

Aqueous effluent treatment system (2) including a separation reactor (4) having a reactor chamber fluidly connected to an aqueous effluent source (3), connected via a pump (5) to an inlet (34) of the reactor chamber, a fluid extraction system (6) connected ...

2020

Report of recent experiments with the European 1 MW, 170 GHz CW and SP prototype gyrotrons for ITER

Stefano Alberti, Minh Quang Tran, Jean-Philippe Hogge, Christian Schlatter, Francisco Sanchez, Ioannis Pagonakis, Martin Schmid, Konstantinos Avramidis

The European 1 MW, 170 GHz industrial CW prototype gyrotron has been designed within EGYC (European GYrotron Consortium) in collaboration with the industrial partner Thales Electron Devices (TED) and under the coordination of Fusion for Energy (F4E). This ...

E D P SCIENCES2019

Metrology techniques for the verification of the alignment of the EU gyrotron prototype for ITER

Stefano Alberti, Jean-Philippe Hogge, Francisco Sanchez, Ioannis Pagonakis, Konstantinos Avramidis

The EU gyrotron for the ITER Electron Cyclotron (EC) heating system has been developed in coordinated efforts of the EGYC Consortium, Thales ED (TED) and Fusion for Energy (F4E) and under the supervision of ITER Organization Central Team. After the success ...

E D P SCIENCES2019

Design and implementation of quasi-optical components for the upgrade of the TCV EC-system

Timothy Goodman, Stefano Alberti, Jean-Philippe Hogge, Laurie Porte, Matthieu Toussaint, Florian Ramseyer

The EC-system of the TCV tokamak is progressively being upgraded with the addition of two MW-class dual-frequency gyrotrons (84 and 126 GHz/2s/1MW). In order to connect the two gyrotrons to the existing low field side and top launchers, new waveguide routi ...

ELSEVIER SCIENCE SA2019

Towards Advanced Fusion Gyrotrons: 2018 Update on Activities within EUROfusion

Stefano Alberti, Minh Quang Tran, Ioannis Pagonakis, Martin Schmid, Konstantinos Avramidis

During the ongoing pre-concept phase (2014 - 2020) for a possible future European DEMOnstration Fusion Power Plant (DEMO) the activities within EUROfusion WP HCD EC Gyrotron R&D and Advanced Developments are focusing on options for near-term solutions, and ...

E D P SCIENCES2019

Modeling of parasitic oscillations in smooth-wall circular symmetric dielectric-loaded gyrotron beam ducts

Stefano Alberti, Jean-Philippe Hogge, Jérémy Genoud

The self-consistent simulation of the electron beam interaction was performed in the presence of a lossy dielectric layer in the smooth-wall beam duct of a gyrotron oscillator. For this purpose, the linear and spectral code TWANGlinspec was extended. In th ...

AMER INST PHYSICS2019

Advanced linear models for gyro-backward wave instabilities in gyrotrons

Jérémy Genoud

Parasitic oscillations excitation is one of the main point hindering high-power gyrotron operation for fusion application. These instabilities, besides being dangerous for the gyrotron components, could possibly degrade the electron beam quality before it ...

EPFL2019

Enhanced operation of the Eu Ec test facility

Timothy Goodman, Stefano Alberti, Jean-Philippe Hogge, Damien Fasel, Ugo Siravo, Jérémie Dubray, Albert Perez

A Test Facility (TF) has been designed and installed at SPC to allow for the commissioning of the EU gyrotrons developed in view of their integration to the ITER EC system. The first phase of operation of this TF was dedicated to the development of the EU ...

ELSEVIER SCIENCE SA2019

Diamond Window Technology for Electron Cyclotron Heating and Current Drive: State of the Art

Konstantinos Avramidis

Nuclear fusion power plants require electron cyclotron (EC) heating and current drive (H&CD) systems for plasma heating and stabilization. High-power microwave beams between 1 and 2?MW generated by gyrotrons propagate in a dedicated waveguide transmission ...

TAYLOR & FRANCIS INC2019

Parasitic Oscillations in Smooth-Wall Circular Symmetric Gyrotron Beam Ducts

Stefano Alberti, Jérémy Genoud, Minh Quang Tran, Jean-Philippe Hogge, Trach-Minh Tran, Konstantinos Avramidis

In order to study parasitic oscillation that may occur in a realistic beam duct upstream to the gyrotron cavity, the self-consistent linear and spectral code TWANGlinspec has been modified. The large inhomogeneities in the smooth-wall beam duct geometry or ...

2018

Study of additive manufactured microwave cavities for pulsed optically pumped atomic clock applications

Anja Skrivervik, Emile Jacques de Rijk

Additive manufacturing (AM) of passive microwave components is of high interest for the cost-effective and rapid prototyping or manufacture of devices with complex geometries. Here, we present an experimental study on the properties of recently demonstrate ...

AIP American Institute of Physics2018

Linear and non-linear studies of spurious backward-wave instabilities in a smooth-wall gyrotron beam duct

Stefano Alberti, Jérémy Genoud, Trach-Minh Tran

Recently developed self-consistent models for beam-wave interaction simulations of a gyrotron oscillator are used to study spurious backward-wave instabilities in smooth-wall metallic beam ducts. Starting from a simple case with a basic geometry, the influ ...

2017