Taborelli, M.

Paper	Title	Page
WEPMN070	High Power Test of an X-band Slotted-Iris Accelerator Structure at NLCTA	2191
	S. Doebert, R. Fandos, A. Grudiev, S. T. Heikkinen, J. A. Rodriguez, M. Taborelli, W. Wuensch CERN, Geneva C. Adolphsen, L. Laurent SLAC, Menlo Park, California
	The CLIC study group at CERN has built two X-band HDS (Hybrid Damped Structure) accelerating structures for high-power testing in NLCTA at SLAC. These accelerating structures are novel with respect to their rf-design and their fabrication technique. The eleven-cell constant impedance structures, one made out of copper and one out of molybdenum, are assembled from clamped high-speed milled quadrants. They feature the same heavy higher-order-mode damping as nominal CLIC structures achieved by slotted irises and radial damping waveguides for each cell. The X-band accelerators are exactly scaled versions of structures tested at 30 GHz in the CLIC test facility, CTF3. The results of the X-band tests are presented and compared to those at 30 GHz to determine frequency scaling, and are compared to the extensive copper data from the NLC structure development program to determine material dependence and make a basic validation of the HDS design.
WEPMN071	High RF Power Production for CLIC	2194
	I. Syratchev, E. Adli, D. Schulte, M. Taborelli CERN, Geneva
	The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and excite preferentially the synchronous mode. The RF power produced (several hundred MW) is collected at the downstream end of the structure by means of the Power Extractor and delivered to the main linac structure. The PETS geometry is a result of multiple compromises between beam stability and main linac RF power needs. Another requirement is to provide local RF power termination in case of accelerating structure failure (ON/OFF capability). Surface electric and magnetic fields, power extraction method, HOM damping, ON/OFF capability and fabrication technology were all evaluated to provide a reliable design.
WEPMN072	Material Selection and Characterization for High Gradient RF Applications	2197
	M. Taborelli, G. Arnau-Izquierdo, S. Calatroni, S. T. Heikkinen, T. Ramsvik, S. Sgobba, W. Wuensch CERN, Geneva
	The selection of candidate materials for the accelerating cavities of the Compact LInear Collider (CLIC) is carried out in parallel with high power RF testing. The DC breakdown field of copper, copper alloys, refractory metals, titanium and aluminium have been measured with a dedicated setup. Higher maximum fields are obtained for refractory metals and for titanium, which exhibits important damages after conditioning. Fatigue behaviour of copper alloys has been studied for surface and bulk by pulsed laser irradiation and ultrasonic excitation, respectively. The selected copper alloys show consistently higher fatigue resistance than copper in both experiments. RF tests are planned. In order to obtain the best local properties a bi-metallic assembly is being studied for the accelerating structures. The mechanical strength of junctions of molybdenum and copper-zirconium C15000, made either by Hot Isostatic Pressing or explosion bonding was evaluated. The reliability of the results obtained with either technique should be improved. Testing in DC and RF is continued in order to select materials for a bi-metal exhibiting superior properties with respect to the combination C15000-Mo.
FROBC01	30 GHz High-Gradient Accelerating Structure Test Results	3818
	J. A. Rodriguez, G. Arnau-Izquierdo, R. Corsini, S. Doebert, R. Fandos, A. Grudiev, I. Syratchev, M. Taborelli, F. Tecker, P. Urschutz, W. Wuensch CERN, Geneva H. Aksakal, Z. Nergiz Ankara University, Faculty of Sciences, Tandogan/Ankara M. Johnson UU/ISV, Uppsala O. M. Mete Ankara University, Faculty of Engineering, Tandogan, Ankara
	The CLIC study is high power testing accelerating structures in a number of different materials and accelerating structure designs to understand the physics of breakdown, determine the appropriate scaling of performance and in particular to find ways to increase achievable accelerating gradient. The most recent 30 GHz structures which have been tested include damped structures in copper, molybdenum, titanium and aluminum. The results from these new structures are presented and compared to previous ones to determine dependencies of quantities such as achievable accelerating gradient, pulse length, power flow, conditioning rate and breakdown rate.
	Slides