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Title: Solid core dipoles and switching power supplies: Lower cost light sources?

Abstract

As a result of improvements in power semiconductors, moderate frequency switching supplies can now provide the hundreds of amps typically required by accelerators with zero-to-peak noise in the kHz region ~ 0.06% in current or voltage mode. Modeling was undertaken using a finite electromagnetic program to determine if eddy currents induced in the solid steel of CEBAF magnets and small supplemental additions would bring the error fields down to the 5ppm level needed for beam quality. The expected maximum field of the magnet under consideration is 0.85 T and the DC current required to produce that field is used in the calculations. An additional 0.1% current ripple is added to the DC current at discrete frequencies 360 Hz, 720 Hz or 7200 Hz. Over the region of the pole within 0.5% of the central integrated BdL the resulting AC field changes can be reduced to less than 1% of the 0.1% input ripple for all frequencies, and a sixth of that at 7200 Hz. Doubling the current, providing 1.5 T central field, yielded the same fractional reduction in ripple at the beam for the cases checked. A small dipole was measured at 60, 120, 360 and 720 Hz in twomore » conditions and the results compared to the larger model for the latter two frequencies with surprisingly good agreement. Thus, for light sources with aluminum vacuum vessels and full energy linac injection, the combination of solid core dipoles and switching power supplies may result in significant cost savings.« less

Authors:
 [1];  [1]
  1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1179008
Report Number(s):
JLAB-ACO-14-1854; DOE/OR/23177-3021; arXiv:1502.06574
Journal ID: ISSN 1748-0221
DOE Contract Number:  
AC05-06OR23177
Resource Type:
Journal Article
Journal Name:
Journal of Instrumentation
Additional Journal Information:
Journal Volume: 10; Journal Issue: 05; Journal ID: ISSN 1748-0221
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
accelerator subsystems and technologies; acceleration cavities and magnets superconducting (high-temperature superconductor); radiation hardened magnets; normal-conducting; permanent magnet devices; wigglers and undulators

Citation Formats

Benesch, Jay, and Philip, Sarin. Solid core dipoles and switching power supplies: Lower cost light sources?. United States: N. p., 2015. Web. doi:10.1088/1748-0221/10/05/P05001.
Benesch, Jay, & Philip, Sarin. Solid core dipoles and switching power supplies: Lower cost light sources?. United States. doi:10.1088/1748-0221/10/05/P05001.
Benesch, Jay, and Philip, Sarin. Tue . "Solid core dipoles and switching power supplies: Lower cost light sources?". United States. doi:10.1088/1748-0221/10/05/P05001.
@article{osti_1179008,
title = {Solid core dipoles and switching power supplies: Lower cost light sources?},
author = {Benesch, Jay and Philip, Sarin},
abstractNote = {As a result of improvements in power semiconductors, moderate frequency switching supplies can now provide the hundreds of amps typically required by accelerators with zero-to-peak noise in the kHz region ~ 0.06% in current or voltage mode. Modeling was undertaken using a finite electromagnetic program to determine if eddy currents induced in the solid steel of CEBAF magnets and small supplemental additions would bring the error fields down to the 5ppm level needed for beam quality. The expected maximum field of the magnet under consideration is 0.85 T and the DC current required to produce that field is used in the calculations. An additional 0.1% current ripple is added to the DC current at discrete frequencies 360 Hz, 720 Hz or 7200 Hz. Over the region of the pole within 0.5% of the central integrated BdL the resulting AC field changes can be reduced to less than 1% of the 0.1% input ripple for all frequencies, and a sixth of that at 7200 Hz. Doubling the current, providing 1.5 T central field, yielded the same fractional reduction in ripple at the beam for the cases checked. A small dipole was measured at 60, 120, 360 and 720 Hz in two conditions and the results compared to the larger model for the latter two frequencies with surprisingly good agreement. Thus, for light sources with aluminum vacuum vessels and full energy linac injection, the combination of solid core dipoles and switching power supplies may result in significant cost savings.},
doi = {10.1088/1748-0221/10/05/P05001},
journal = {Journal of Instrumentation},
issn = {1748-0221},
number = 05,
volume = 10,
place = {United States},
year = {2015},
month = {5}
}