The CERN Resonant WISP Search (CROWS)
The CERN Resonant WISP Search (CROWS)

Author: Betz, Michael

Publisher: KIT Scientific Publishing

Published: 2014-05-05

Total Pages: 212

ISBN-13: 3731501996

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The subject of this work is the design, implementation and first results of the "CERN Resonant WISP Search" (CROWS), which probes the existence of Axion Like Particles and Hidden Sector Photons (HSPs) using microwave techniques. By exploiting low loss cavity resonators, multiple layers of electromagnetic shielding and a micro-Hz bandwidth detection scheme, new exclusion limits could be set. For HSPs, sensitivity was improved by a factor of 7 compared to previous laboratory experiments.

The CERN Resonant WISP Search (CROWS)
The CERN Resonant WISP Search (CROWS)

Author: Michael Betz

Publisher:

Published: 2020-10-09

Total Pages: 206

ISBN-13: 9781013282881

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The subject of this work is the design, implementation and first results of the ""CERN Resonant WISP Search"" (CROWS), which probes the existence of Axion Like Particles and Hidden Sector Photons (HSPs) using microwave techniques. By exploiting low loss cavity resonators, multiple layers of electromagnetic shielding and a micro-Hz bandwidth detection scheme, new exclusion limits could be set. For HSPs, sensitivity was improved by a factor of 7 compared to previous laboratory experiments. This work was published by Saint Philip Street Press pursuant to a Creative Commons license permitting commercial use. All rights not granted by the work's license are retained by the author or authors.

Design and Experimental Investigation of a Second Harmonic 20 kW Class 28 GHz Gyrotron for Evaluation of New Emitter Technologies
Design and Experimental Investigation of a Second Harmonic 20 kW Class 28 GHz Gyrotron for Evaluation of New Emitter Technologies

Author: Malygin, Anton

Publisher: KIT Scientific Publishing

Published: 2016-12-16

Total Pages: 162

ISBN-13: 3731505843

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Gyrotrons are high-power mm-wave tubes. Here, the design, construction and experimental investigation of a 20 kW, 28 GHz gyrotron (2nd harmonic) are reported. This tube was designed to evaluate new emitters for future highly efficient and reliable fusion gyrotrons and for material processing applications. Following experimental results have been achieved in CW operation: 22.5 kW output power at 23.4 kV electron beam voltage and 2.23 A beam current with the world record efficiency of 43 %.

Temperature- and Time-Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites
Temperature- and Time-Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites

Author: Prastiyanto, Dhidik

Publisher: KIT Scientific Publishing

Published: 2016-03-15

Total Pages: 204

ISBN-13: 3731504243

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In this book a test set for dielectric measurements at 2.45 GHz during curing of polymer composites is developed. Fast reconstruction is solved using a neural network algorithm. Modeling of the curing process at 2.45 GHz using both dielectric constant and dielectric loss factor results in more accurate model compared to low frequency modelling that only uses the loss factor. Effect of various hardeners and different amount of filler is investigated.

Energy-efficient, scalable and modular industrial microwave applicator for high temperature alkaline hydrolysis of PET
Energy-efficient, scalable and modular industrial microwave applicator for high temperature alkaline hydrolysis of PET

Author: Ramopoulos, Vasileios

Publisher: KIT Scientific Publishing

Published: 2023-01-27

Total Pages: 162

ISBN-13: 3731510995

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Microwave-assisted alkaline hydrolysis of PET can be 20 times faster and at lower temperatures. This work presents a novel industrial microwave applicator at 2.45 GHz with homogeneous distribution to support this reaction, which allows an efficient and continuous operation. In addition, an innovative dielectric and calorimetric measurements setup is presented. Furthermore, the modelling of the reaction kinetics based on the measured dielectric parameters is presented.

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.

Feasibility and Operational Limits for a 236 GHz Hollow-Cavity Gyrotron for DEMO
Feasibility and Operational Limits for a 236 GHz Hollow-Cavity Gyrotron for DEMO

Author: Kalaria, Parth Chandulal

Publisher: KIT Scientific Publishing

Published: 2017-11-08

Total Pages: 270

ISBN-13: 373150717X

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The DEMOnstration fusion power plant (DEMO) will be the first fusion reactor, which is intended to generate net electrical power. For successful operation of DEMO, high-power gyrotrons with operating frequencies up to 240 GHz are required for plasma heating and stabilization. In this work, a systematic feasibility study and tolerance analysis are performed for the conventional-type hollow-cavity DEMO gyrotrons. The various approaches are also suggested to identify its operational limits.

Pushing the KIT 2 MW Coaxial-Cavity Short-Pulse Gyrotron Towards a DEMO Relevant Design
Pushing the KIT 2 MW Coaxial-Cavity Short-Pulse Gyrotron Towards a DEMO Relevant Design

Author: Ruess, Sebastian

Publisher: KIT Scientific Publishing

Published: 2021-01-22

Total Pages: 190

ISBN-13: 3731510243

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Magnetic fusion is one approach to generate thermonuclear fusion power in an environmental friendly way. The Electron Cyclotron Resonance Heating is considered as the major concept for startup, heating and control of the fusion plasma. Megawatt-class gyrotrons generate the required microwave power. This work focuses on advanced key components and technologies for a DEMO relevant 2 MW gyrotron. One major focus is on the development of advanced Magnetron Injection Guns. Another focus is on the red