Download or read book The CERN Resonant WISP Search CROWS written by Betz, Michael and published by KIT Scientific Publishing. This book was released on 2014-05-05 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The CERN Resonant WISP Search CROWS written by Michael Betz and published by . This book was released on 2020-10-09 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Design and Experimental Investigation of a Second Harmonic 20 kW Class 28 GHz Gyrotron for Evaluation of New Emitter Technologies written by Malygin, Anton and published by KIT Scientific Publishing. This book was released on 2016-12-16 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 %.

Download or read book Conceptual Studies of Multistage Depressed Collectors for Gyrotrons written by Wu, Chuanren and published by KIT Scientific Publishing. This book was released on 2019-09-09 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Temperature and Time Dependent Dielectric Measurements and Modelling on Curing of Polymer Composites written by Prastiyanto, Dhidik and published by KIT Scientific Publishing. This book was released on 2016-03-15 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book A high voltage pulsed power modulator for fast rising arbitrary waveforms written by Hochberg, Martin and published by KIT Scientific Publishing. This book was released on 2020-02-19 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy efficient scalable and modular industrial microwave applicator for high temperature alkaline hydrolysis of PET written by Ramopoulos, Vasileios and published by KIT Scientific Publishing. This book was released on 2023-01-27 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Automated Mode Recovery and Electronic Stability Control for Wendelstein 7 X Gyrotrons written by Wilde, Fabian and published by KIT Scientific Publishing. This book was released on 2024-08-07 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Feasibility and Operational Limits for a 236 GHz Hollow Cavity Gyrotron for DEMO written by Kalaria, Parth Chandulal and published by KIT Scientific Publishing. This book was released on 2017-11-08 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Pushing the KIT 2 MW Coaxial Cavity Short Pulse Gyrotron Towards a DEMO Relevant Design written by Ruess, Sebastian and published by KIT Scientific Publishing. This book was released on 2021-01-22 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Influence of Emitter Surface Roughness and Emission Inhomogeneity on Efficiency and Stability of High Power Fusion Gyrotrons written by Zhang, Jianghua and published by KIT Scientific Publishing. This book was released on 2016-11-30 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing demand for powerful, reliable, and efficient gyrotron oscillators for Electron Cyclotron Resonance Heating (ECRH) in fusion plasma experiments requires a close look at the various factors in gyrotrons that determine gyrotron performance. In this frame, the influence of emitter surface roughness, emission inhomogeneity, and secondary electron generation on gyrotron operation is presented, with focus on Low Frequency Oscillations (LFOs) and Electron Beam Halo (EBH) generation.

Download or read book Systematic Study of Key Components for a Coaxial Cavity Gyrotron for DEMO written by Franck, Joachim and published by KIT Scientific Publishing. This book was released on 2017-05-11 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physical design of cavity and magnetron injection gun (MIG) for a realistic, DEMO-compatible, coaxial-cavity 238 GHz 2 MW CW fusion gyrotron is developed in this work, having auxiliary frequencies at 170 GHz and 204 GHz. Novel systematic approaches towards multi-frequency mode selection, magnet requirements, and MIG design are presented. Mode deterioration and voltage depression variation due to insert misalignment versus cavity wall and/or versus electron beam are studied.

Download or read book New Type of sub THz Oscillator and Amplifier Systems Based on Helical Type Gyro TWTs written by Marek, Alexander and published by KIT Scientific Publishing. This book was released on 2023-01-26 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Time dependent spectrum analysis of high power gyrotrons written by Schlaich, Andreas and published by KIT Scientific Publishing. This book was released on 2015-08-06 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, a novel measurement system for the analysis of the gyrotron RF output spectrum was developed. It enables unprecedented time dependent measurements within a large bandwidth, dynamic range and unambiguous RF indication in the entire D-Band (110-170 GHz). Special attention was given to the investigation of parasitic RF oscillations, and the analysis of the interplay of thermal cavity expansion and ionization-based space charge neutralization at the start of long RF pulses.

Download or read book A First 2 MW Class 136 170 204 GHz Multi Frequency Gyrotron Pre Prototype for DEMO Design Construction and Key Components Verification written by Ruess, Tobias and published by KIT Scientific Publishing. This book was released on 2023-10-26 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book MultPhysics Modelling towards the Stabilization of PAN Fibers with Microwaves Based on Experimental Data written by Hofele, Julia and published by KIT Scientific Publishing. This book was released on 2024-07-10 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Adaptive and Intelligent Temperature Control of Microwave Heating Systems with Multiple Sources written by Sun, Yiming and published by KIT Scientific Publishing. This book was released on 2016-04-28 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, an innovative real-time microwave control approach is proposed, to improve the temperature homogeneity under microwave heating. Multiple adaptive or intelligent control structures have been developed, including the model predictive control, neural network control and reinforcement learning control methods. Experimental results prove that these advanced control methods can effectively reduce the final temperature derivations and improve the temperature homogeneity.