Compensating the unequal bunch spacing in the NLC damping rings
- Stanford Linear Accelerator Center, CA (United States)
- KEK, National Laboratory for High Energy Physics, Oho, Tsukuba-shi, Ibaraki-ken (Japan)
The damping rings of the Next Linear Collider (NLC), at any given time, will contain four trains of 90 bunches each. Within each train the bunches populate adjacent buckets and between trains there is a gap that extends over 43 buckets. A consequence of an uneven filling scheme is that within each train the synchronous phase will vary from bunch to bunch. In the NLC after extraction the beam enters the bunch compressor and then the X-band linac. The phase variation in the ring, if uncompensated, will lead to a phase variation in the X-band linac which, in turn, will result in an unacceptable spread in the final energy of the individual bunches of a train. The synchronous phase variation, however, can be compensated, either in the damping ring itself or in the bunch compressor that follows. The subject of this paper is compensation in the damping ring. In this report we begin by finding the synchronous phase variation in damping rings with bunch trains and gaps of arbitrary length. These results are then applied to the parameters of the NLC damping rings. Finally, we study two methods of compensating this phase variation: in the first method two passive subharmonic cavities are employed, and in the second the klystron output is varied as a function of time. We find that, for the NLC, a nominal phase variation of 6 degrees within a train can be reduced by almost an order of magnitude by either method of compensation, with the cost of the second method being an extra 10% in output power capability of the klystron.
- Research Organization:
- Stanford Linear Accelerator Center, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 627978
- Report Number(s):
- SLAC-PUB-7189; CONF-960621-; ON: DE97009066; TRN: AD-a339 883
- Resource Relation:
- Conference: EPAC `96: 5. European particle accelerator conference, Barcelona (Spain), 10-14 Jun 1996; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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