| Paper |
Title |
Page |
| MOPLS095 |
Investigations of DC Breakdown Fields
|
777 |
| |
- T. Ramsvik, S. Calatroni, A. Reginelli, M. Taborelli
CERN, Geneva
|
|
| |
The need for high accelerating gradients for the future 30 GHz multi-TeV e+e- Compact Linear Collider (CLIC) at CERN has triggered a comprehensive study of DC breakdown fields of metals in UHV. The experimental setup is based on a capacitor discharge across a gap junction. The simple design and fully automated computer control enable breakdown fields and dark current of numerous materials to be measured. The study shows that Mo, W and Ti reach high breakdown fields, and are thus good candidates for the iris material of CLIC structures. For untreated Mo the breakdown field is higher than Cu but the conditioning speed is slower. Ti, on the other hand, shows acceptable conditioning speeds, but material erosion makes this solution problematic. Feasible solutions to increase the spark conditioning speed for the case of Mo are presented together with attempts to prevent Ti erosion. For some of the materials studied a significant reduction in the saturated breakdown field was observed upon gas exposure during intensive spark conditioning. As an example, a 50% decrease of the breakdown field of Mo is recorded when spark conditioning is carried out in an environment of 10-5 mbar air.
|
|
| MOPLS103 |
A High-gradient Test of a 30 GHz Molybdenum-iris Structure
|
801 |
| |
- W. Wuensch, C. Achard, H.-H. Braun, G. Carron, R. Corsini, S. Doebert, R. Fandos, A. Grudiev, E. Jensen, T. Ramsvik, J.A. Rodriguez, J.P.H. Sladen, I. Syratchev, M. Taborelli, F. Tecker, P. Urschütz, I. Wilson
CERN, Geneva
- H. Aksakal
Ankara University, Faculty of Sciences, Tandogan/Ankara
- Ö.M. Mete
Ankara University, Faculty of Engineering, Tandogan, Ankara
|
|
| |
The CLIC study is investigating a number of different materials as part of an effort to find ways to increase achievable accelerating gradient. So far, a series of rf tests have been made with a set of identical-geometry structures: a tungsten-iris 30 GHz structure, a molybdenum-iris 30 GHz structure and a scaled molybdenum-iris X-band structure. A second molybdenum-iris 30 GHz structure of the same geometry has now been tested in CTF3 with pulse lengths up to 350 ns. The new results are presented and compared to those of the previous structures to determine dependencies of quantities such as accelerating gradient, material, frequency, pulse length, power flow, conditioning rate and breakdown rate.
|
|