Abstract
Accelerating gradients in excess of $100\text{ }\text{ }\mathrm{MV}/\mathrm{m}$, at very low breakdown rates, have been successfully achieved in numerous prototype CLIC accelerating structures. The conditioning and operational histories of several structures, tested at KEK and CERN, have been compared and there is clear evidence that the conditioning progresses with the number of rf pulses and not with the number of breakdowns. This observation opens the possibility that the optimum conditioning strategy, which minimizes the total number of breakdowns the structure is subject to without increasing conditioning time, may be to never exceed the breakdown rate target for operation. The result is also likely to have a strong impact on efforts to understand the physical mechanism underlying conditioning and may lead to preparation procedures which reduce conditioning time.
Highlights
The CLIC accelerating gradient target [1] of 100 MV=m, pulse length of around 200 ns and breakdown rate (BDR, i.e., number of pulses with breakdown divided by total number of pulses) in the range of 10−7 1=pulse=m is routinely achieved in prototype CLIC accelerating structures [2]
A quantity based on local power flow [4] appears to determine the limiting gradient as a function of rf design for a given manufacturing procedure
Prototype structures are manufactured reproducibly by KEK/SLAC and CERN according to a procedure developed in the NLC/GLC linear collider study [5]
Summary
The CLIC accelerating gradient target [1] of 100 MV=m, pulse length of around 200 ns and breakdown rate (BDR, i.e., number of pulses with breakdown divided by total number of pulses) in the range of 10−7 1=pulse=m is routinely achieved in prototype CLIC accelerating structures [2]. A dedicated effort to understand and reduce rf conditioning time has been initiated and the first step in this effort has been to rigorously compare the conditioning data from a set of similar rf design prototype CLIC accelerating structures. This analysis has surprisingly produced clear evidence that the conditioning progresses as the number of rf pulses and not as the number of breakdowns. In addition the insight will be used as input for the investigation of new structure preparation procedures to reduce the rf conditioning time by mimicking the effect of rf pulses in a cost effective way
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
