New Type of sub-THz Oscillator and Amplifier Systems Based on Helical-Type Gyro-TWTs
New Type of sub-THz Oscillator and Amplifier Systems Based on Helical-Type Gyro-TWTs

Author: Marek, Alexander

Publisher: KIT Scientific Publishing

Published: 2023-01-26

Total Pages: 322

ISBN-13: 3731512505

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This work presents the development of a new sub-THz source for the generation of trains of coherent high-power ultra-short pulses at 263 GHz via passive mode-locking of two coupled helical gyro-TWTs. For the first time, it is shown that the operation of such passive mode-locked helical gyro-TWTs in the hard excitation regime is of particular importance to reach the optimal coherency of the generated pulses. This could be of particular interest for some new time-domain DNP-NMR methods.

MultPhysics Modelling towards the Stabilization of PAN Fibers with Microwaves Based on Experimental Data
MultPhysics Modelling towards the Stabilization of PAN Fibers with Microwaves Based on Experimental Data

Author: Hofele, Julia

Publisher: KIT Scientific Publishing

Published: 2024-07-10

Total Pages: 174

ISBN-13: 3731513501

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High energy demand is one reason for high costs of carbon fibers. One option to decrease them is to use microwave heating instead of conventional heating. In this work, steps towards a microwave assisted process during the stabilization phase are presented. In-situ dielectric measurements are performed and a reaction kinetics model is setup in connection to the dielectric loss. This allows to calculate a stabilization degree and fiber temperatures leading to a basic process understanding.

Automated Mode Recovery and Electronic Stability Control for Wendelstein 7-X Gyrotrons
Automated Mode Recovery and Electronic Stability Control for Wendelstein 7-X Gyrotrons

Author: Wilde, Fabian

Publisher: KIT Scientific Publishing

Published: 2024-08-07

Total Pages: 272

ISBN-13: 3731511606

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Magnetic confinement fusion relies on plasma heating and plasma control using gyrotron oscillators providing at megawatt power levels. The operational reliability decreases when operating at the performance limits due to increasing parasitic mode activity. This work demonstrates for the first time the automated, fast recovery of nominal gyrotron operation during a pulse by exploiting the hysteretic gyrotron behaviour after a mode switch being in use at the Wendelstein 7-X ECRH facility.

A First 2 MW-Class (136)/170/204 GHz Multi-Frequency Gyrotron Pre-Prototype for DEMO: Design, Construction and Key Components Verification
A First 2 MW-Class (136)/170/204 GHz Multi-Frequency Gyrotron Pre-Prototype for DEMO: Design, Construction and Key Components Verification

Author: Ruess, Tobias

Publisher: KIT Scientific Publishing

Published: 2023-10-26

Total Pages: 258

ISBN-13: 3731513099

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Ein Gyrotron wird in magnetisch eingeschlossenen Plasmaexperimenten für Heizung, Stromtrieb, Plasmastabilisierung und Plasmadiagnostik verwendet. In dieser Arbeit wird der erste Entwurf und Bau eines Mehrfrequenz-/Mehrzweck Pre-Prototyp Gyrotrons in koaxialer Technologie vorgestellt, das bei (136)/170/204 GHz mit einer Ausgangsleistung von 2 MW arbeitet. Dies ist der erste Schritt zum Betrieb bei Frequenzen bis zu 240 GHz unter Verwendung der Koaxialhohlraum-Gyrotrontechnologie. - A gyrotron is used in magnetically confined plasma experiments for heating, current drive, plasma stabilization and plasma diagnostics. This work presents the first design and construction of a multi-frequency / multi-purpose coaxial-cavity pre-prototype gyrotron operating at (136)/170/204 GHz with an output power of 2 MW. It is the first step towards operating frequencies up to 240 GHz using the coaxial-cavity gyrotron technology.

Millimeter-Wave Gyrotron Traveling-Wave Tube Amplifiers
Millimeter-Wave Gyrotron Traveling-Wave Tube Amplifiers

Author: Chao-Hai Du

Publisher: Springer

Published: 2014-05-29

Total Pages: 200

ISBN-13: 3642547281

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A gyrotron traveling-wave amplifier (gyro-TWT) with the high-power and broad-band capabilities is considered as a turn-on key for next generation high-resolution radar. The book presents the most advanced theory, methods and physics in a gyro-TWT. The most challenging problem of instability competition has been for the first time addressed in a focused and systematic way and reported via concise states and vivid pictures. The book is likely to meet the interest of researchers and engineers in radar and microwave technology, who would like to study the gyro-TWTs and to promote its application in millimeter-wave radars. Chao-Hai Du and Pu-Kun Liu are both professors at Peking University.

Gyrotrons
Gyrotrons

Author: Machavaram V. Kartikeyan

Publisher: Springer Science & Business Media

Published: 2013-03-14

Total Pages: 234

ISBN-13: 3662076373

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Drawing on the author's wide experience, this book gives a comprehensive review of the state of the art in gyrotron technology, covering the theory, design and applications. The book includes an extensive references list which provides an excellent guide to the related literature.

Introduction to Terahertz Electronics
Introduction to Terahertz Electronics

Author: Jae-Sung Rieh

Publisher: Springer Nature

Published: 2020-10-01

Total Pages: 363

ISBN-13: 3030518426

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This book provides a practical guide to terahertz electronics, especially for readers with an electronics background. The author guides readers through the all the key concepts of terahertz electronics, including terahertz sources, detectors, and waveguides, together with reviews on key terahertz applications on spectroscopy, imaging, communication, and radar. This book will serve as a handy reference for graduate students and engineers in the field of terahertz with a viewpoint from electronics. Presents the topic of terahertz from electronics viewpoint; Designed to be particularly helpful for the readers familiar with semiconductor devices and circuits; Enables optics-based terahertz researchers to understand terahertz electronics; Based on the author’s extensive experience from both industry and academia.

Experimental Approaches of NMR Spectroscopy
Experimental Approaches of NMR Spectroscopy

Author: The Nuclear Magnetic Resonance Society of Japan

Publisher: Springer

Published: 2017-11-23

Total Pages: 634

ISBN-13: 9811059667

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This book describes the advanced developments in methodology and applications of NMR spectroscopy to life science and materials science. Experts who are leaders in the development of new methods and applications of life and material sciences have contributed an exciting range of topics that cover recent advances in structural determination of biological and material molecules, dynamic aspects of biological and material molecules, and development of novel NMR techniques, including resolution and sensitivity enhancement. First, this book particularly emphasizes the experimental details for new researchers to use NMR spectroscopy and pick up the potentials of NMR spectroscopy. Second, the book is designed for those who are involved in either developing the technique or expanding the NMR application fields by applying them to specific samples. Third, the Nuclear Magnetic Resonance Society of Japan has organized this book not only for NMR members of Japan but also for readers worldwide who are interested in using NMR spectroscopy extensively.

Electromagnetic Theory and Applications in Beam-wave Electronics
Electromagnetic Theory and Applications in Beam-wave Electronics

Author: B. N. Basu

Publisher: World Scientific

Published: 1996

Total Pages: 496

ISBN-13: 981022320X

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This book is divided into two parts. The first part deals with basic electromagnetic and the second part with beam-wave electronics related to growing-wave devices including 'slow-wave' travelling-wave tubes and 'fast-wave' gyro-travelling-wave tubes. The first part is a prerequisite for the second part, while the second part covers the applications of the topics discussed in the first part. These two parts put together make the volume a self-contained treatise. In the specific applications considered, time-independent field concepts are exemplified in the problems related to the formation of an electron beam by an electron gun, the confinement of an electron beam by a magnetic focusing structure, etc. Similarly, time-dependent field concepts are exemplified in problems related to propagation through a slow-wave structure and amplification in growing-wave electron beam devices, such as travelling-wave tubes, double-stream amplifiers, beam-plasma amplifiers and gyro-travelling-wave tubes. All throughout the text, stress is given to provide complete analytical deductions with full mathematical details and present the state-of-the-art concepts.