Paper | Title | Page |
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MOPD29 | Transverse Matching Progress of the SNS Superconducting Linac | 126 |
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Experience using laser-wire beam profile measurement to perform transverse beam matching in the SNS superconducting linac is discussed. As the SNS beam power is ramped up to 1 MW, transverse matching should become more critical to control beam loss and residual activation. In our experiments, however, beam loss in the SC linac is not very sensitive to the matching condition. In addition, we have encountered some difficulties in performing a satisfactory transverse beam matching with the envelope model currently available in our XAL software framework. Offline data analysis from multi-particle tracking simulation shows that the accuracy of the current matching algorithm may not be sufficient to the SC linac. |
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MOPD41 | Impact of Uncaught Foil-Stripped Electrons in the Spallation Neutron Source Ring | 156 |
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We use the ORBIT particle tracking code to simulate the propagation of 545 keV electrons stripped from 1 GeV H- ions during injection into the Spallation Neutron Source accumulator ring. The electrons propagate in the field of the injection magnet and are subject to scattering at the bottom surface when they are not caught by the electron catcher in the design fashion. The scattered electrons have the potential to intercept and damage local hardware. We model the non-caught electrons and compare our simulated results with experimental observations. |
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TUO2B03 | SNS Injection Foil Experience | 334 |
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The Spallation Neutron Source comprises a 1 GeV, 1.4 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H0 excited states created during the H− charge exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H− beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and contribute to foil and bracket failure. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we will detail these and other interesting failure mechanisms, and describe the improvements we have made to mitigate them. |
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FROP03 | Summary of the Working Group on Accelerator System Design, Injection, and Extraction | 699 |
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We review the presentations and discussions of the Accelerator System Design, Injection and Extraction working group at the 46th ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams. |
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