| Paper |
Title |
Page |
| MOP045 |
Performance of SNS Front End and Warm Linac
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145 |
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- A. V. Aleksandrov, S. Assadi, W. Blokland, P. Chu, S. M. Cousineau, V. V. Danilov, C. Deibele, J. Galambos, S. Henderson, D.-O. Jeon, M. A. Plum, A. P. Shishlo, M. P. Stockli
ORNL, Oak Ridge, Tennessee
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The Spallation Neutron Source accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector, capable of producing one-ms-long pulses at 60Hz repetition rate with 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The 2.5MeV beam from the Front End is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in the Superconducting Linac. With the completion of beam commissioning, the accelerator complex began operation in June 2006. Injector and warm linac performance results will be presented including transverse emittance evolution along the linac, longitudinal bunch profile measurements at the beginning and end of the linac, and the results of a beam loss study.
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| TUP003 |
Spallation Neutron Source Linac Beam Position and Phase Monitor System
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247 |
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- J. F. Power, M. W. Stettler
LANL, Los Alamos, New Mexico
- A. V. Aleksandrov, S. Assadi, W. Blokland, P. Chu, C. Deibele, J. Galambos, C. D. Long, J. Pogge, A. Webster
ORNL, Oak Ridge, Tennessee
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The SNS linac currently has 6x beam position monitors which allow the measurement of both beam position and phase from a single pickup. The signals from the pickup lobes are down converted from either 402.5MHz or 805 MHz to 50-MHz IF signals for processing. The IF signals are synchronously sampled at 40 MHz to generate I and Q signals from which the beam position and phase are calculated. Each BPM sampling reference frequency is locked to a phase-stable 2.5 MHz signal distributed along the linac. The system is continuously calibrated by generating and measuring rf bursts in the processor that travel to the BPM pickup, reflect off of the shorted BPM lobes and return to the processor for re-measurement. The electronics are built in a PCI card format and controlled vith LabVIEW. Details of the system design and performance are presented.
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| TUP032 |
Comparison of SNS Superconducting Cavity Calibration Methods
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315 |
| |
- Y. Zhang, I. E. Campisi, P. Chu, J. Galambos, S. Henderson, D.-O. Jeon, K.-U. Kasemir, A. P. Shishlo
ORNL, Oak Ridge, Tennessee
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Three different methods have been used to calibrate the SNS superconducting cavity RF field amplitude. Two are beam based and the other strictly RF based. One beam based method uses time-of-flight signature matching (phase scan method), and the other uses the beam-cavity interaction itself (drifting beam method). Both of these methods can be used to precisely calibrate the pickup probe of a SC cavity and determine the synchronous phase. The initial comparisons of the beam based techniques at SNS did not achieve the desired precision of 1% due to the influence of calibration errors, noise and coherent interfaces in the system. To date the beam-based SC cavity pickup probe calibrations agree within approximately 4%, comparable to the conventional RF calibrations.
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| TUP084 |
Drifting Beam Application for SNS Superconducting Cavity Setting
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454 |
| |
- P. Chu, Y. Zhang
ORNL, Oak Ridge, Tennessee
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A software application for tuning superconducting linac cavity has been developed and tested at the Spallation Neutron Source (SNS). The application is based on the drifting beam method and the XAL online model. The drifting beam method and the application were proved to be consistent with other cavity tuning method during the SNS commissioning runs. Detail algorithm and data acquisition for the application will be presented.
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