Momentum painting in SNS accumulator ring
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
For 2 MW operations, the peak beam current in the SNS accumulator ring approaches 100 A. Collective effects are a significant concern and the various stability thresholds are monotonic functions of the momentum spread of the beam. Therefore, it is useful to have control of the injected momentum distribution. The energy corrector and spreader cavities were included in the design to allow the operations team to tune the rms energy spread of the injected beam, but these devices have been removed from the baseline. The energy corrector cavity runs at the nominal RF frequency. This device is located downstream of the main linac so that the longitudinal phase of the bunches is roughly proportional to their energy deviation. A proper choice of voltage corrects the centroid energy of the individual bunches. Next, the energy spreader cavity runs at a frequency that is offset from the nominal RF frequency by ~ 100 kHz. This device provides a pseudo-random kick to the individual bunches which increases the rms energy spread of the beam without producing the large momentum tails associated with a debuncher cavity.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1157302
- Report Number(s):
- BNL--105693-2014-IR
- Country of Publication:
- United States
- Language:
- English
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STUDY OF LONGITUDINAL INJECTION/STACKING IN THE SNS ACUMMULATOR RING.
Conference
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Sun Mar 28 23:00:00 EST 1999
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OSTI ID:15016650