Superconducting cavities and modulated RF
If a cavity has an infinite Q/sub o/, 81.5% of the energy contained in a pulse incident upon the cavity is transferred into the cavity by the end of the pulse if the cavity Q/sub e/ is chosen so that the cavity time constant is 0.796 pulse width (T/sub a/). As Q/sug o/ decreases, the energy in the cavity at the end of the pulse decreases very slowly as long as T/sub a/ is much less than the unloaded cavity time constant, T/sub co/. SC cavities with very high Q/sub o/ enable one to obtain very high gradients with a low power cw source. At high gradients, however, one often does not attain the high Q/sub o/ predicted by theory. Therefore, if one is inteerested in attaining maximum energy in the cavity, as is the case for RF processing and diagnostics, for a given available source energy there is no point in keeping the power on for longer than 0.1 T/sub co/ because the energy expended after 0.1 T/sub co/ is wasted. Therefore, to attain high fields at moderate Q/sub o/, pulsed operation is indicated. This note derives the fields and energy stored and dissipated in the cavity when Q/sub e/ is optimized for a given T/sub a/. It shows how to use this data to measure Q/sub o/ of an SC cavity as a function of field level, how to process the cavity with high RF fields, how to operate SC cavities in the pulsed mode to obtain higher efficiencies and gradients. Experimental results are also reported.
- Research Organization:
- Stanford Linear Accelerator Center, CA (USA)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 6505507
- Report Number(s):
- SLAC-PUB-2682; CONF-810314-129; TRN: 81-009466
- Resource Relation:
- Conference: Particle accelerator conference, Washington, DC, USA, 11 Mar 1981
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTING CAVITY RESONATORS
MODULATION
ELECTROMAGNETIC FIELDS
EXPERIMENTAL DATA
PULSE TECHNIQUES
TUNING
CAVITY RESONATORS
DATA
ELECTRONIC EQUIPMENT
EQUIPMENT
INFORMATION
NUMERICAL DATA
RESONATORS
SUPERCONDUCTING DEVICES
430303* - Particle Accelerators- Experimental Facilities & Equipment