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https://doi.org/10.18429/JACoW-IPAC2014-WEPRO047
Title A New Cooling System for Cryocooled Permanent Magnet Undulators at Diamond Light Source
Authors
  • E.C. Longhi, A.G. Miller, E.C.M. Rial, A.J. Rose, J.C. Schoutenpresenter, C.W. Thompson, A. Thomson, J.H. Williams
    DLS, Oxfordshire, United Kingdom
  • C. Monroe
    Monroe Brothers Ltd., Moreton-in-Marsh, United Kingdom
Abstract Cryocooled permanent magnet undulators (CPMUs) using NdFeB magnets around 150K were first proposed by Hara*. These are cooled by using either GM cryocoolers or circulating sub-cooled liquid nitrogen. Due to the heat load from radiation and wakefield heating from the electron beam, temperature gradients can develop along the length of the magnet girders which could be as large as several degrees for the Diamond Light Source (DLS) storage ring operating parameters. Some grades of the magnetic material (NdxPr1-x)2Fe14B have remanence curves versus temperature which increase significantly for temperatures below 150K with peaks below 80K**. This means that the operating temperature of a CPMU using this material can be close to the boiling point of liquid nitrogen. The proposed cooling system for the new DLS CPMU is based on a thermosiphon allowing nitrogen to boil inside the cooling channels without a circulating pump. This has the advantage of absorbing large amounts (>250W) of heat with very small temperature gradients. We report here the results of a prototype magnet beam cooled with a thermosiphon producing a temperature gradient of less than 0.05K along a 2m beam at ~77K.
Footnotes & References * T. Hara et al., Phys Rev Spec Top. Accelerator & Beam, Vol 7, 2004.
** J. Bahrdt et al., AIP Conf. Proc., SRI 2009, Melbourne Australia, vol. 1234, pp. 499-502, 2010.
Paper download WEPRO047.PDF [0.406 MB / 3 pages]
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Conference IPAC2014, Dresden, Germany
Series International Particle Accelerator Conference (5th)
Proceedings Link to full IPAC2014 Proccedings
Session Poster Session, Ronaldo Area
Date 18-Jun-14   16:00–18:00
Main Classification 02 Synchrotron Light Sources and FELs
Sub Classification T15 Undulators and Wigglers
Keywords vacuum, undulator, operation, cryogenics, electron
Publisher JACoW Publishing, Geneva, Switzerland
Editors Christine Petit-Jean-Genaz (CERN, Geneva, Switzerland); Gianluigi Arduini (CERN, Geneva, Switzerland); Peter Michel (HZDR, Dresden, Germany); Volker RW Schaa (GSI, Darmstadt, Germany)
ISBN 978-3-95450-132-8
Published July 2014
Copyright
Copyright © 2014 by JACoW, Geneva, Switzerland     CC-BY Creative Commons License
cc Creative Commons Attribution 3.0