The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper we investigate the potential causes of failure of a diamond window unit employed in the experimental tokamak ASDEX Upgrade in Garching, Germany. The window unit features a double-disc configuration that allows for a more complex transmission spectrum than with a single disc and is used in conjunction with step-tunable gyrotrons for electron-cyclotron heating of fusion plasmas. The window...
The high-power long pulse RF loss properties of CVD diamond windows for ECR heating and plasma stabilization in large fusion devices have been measured by established Fabry-Perot methods [1,2,3]. The dielectric loss is strongly influenced by the surface chemistry of the diamond. Special surface passivation techniques are investigated due to the reduction of the electrical surface conductivity and...
A new ITER torus window assembly with CVD diamond disk and corrugated waveguides is being investigated by using IR imaging and temperature measuring technique during high power RF microwave loading up to 0.5 MW at a frequency of 170 GHz at the JAEA Gyrotron facility. The inserted waveguide structure can minimize the penetration of high order modes into the window cuff or other parts of the window...
CVD diamond is a well known excellent low loss material (tan δ = 0.55 · 10−5) for microwave transmission e.g. in fusion reactors for the ECRH&CD system. Goal of our investigation is to find out other natural dielectric materials with even low loss tangent properties. Tourmaline is a complex structured natural mineral which grows in large crystals. A disk, sliced perpendicular to the c-axis of...
ITER torus windows with CVD diamond disks for high power heating applications (170 GHz, 1-2 MW) have been investigated by different low and high power measurement setups in the frequency range of 90 to 170 GHz. The authors consider the loss mechanisms in diamond material via determination of the frequency dependence of dielectric constant and loss tangent at high frequencies, up to several THz.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.