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  Anders, W.; Hellwig, A.; Knobloch, J.; Pflückhahn, D.; Rotterdam, S.: Cryogenic System for BERLinPro. In: J. G. Weisend ... [Ed.] : ADVANCES IN CRYOGENIC ENGINEERING: Transactions of the Cryogenic Engineering Conference - CEC : 17–21 June 2013, Anchorage, Alaska, USA, 2014 (AIP Conference Proceedings ; 1573). - ISBN 978-0-7354-1201-9, p. 207-214

10.1063/1.4860703

Abstract:
In 2010 Helmholtz-Zentrum Berlin (HZB) received funding to design and build the Berlin Energy Recovery Linac Project BERLinPro. The goal of this compact Energy recovery linac (ERL) is to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1-mm mrad emittance electron beam. The BERLinPro know-how can then be transferred to various ERL-based applications. All accelerating RF cavities including the electron source are based on superconducting technology operated at 1.8 K. A Linde L700 helium liquefier is supplying 4.5 K helium. The subatmospheric pressure of 16 mbar of the helium bath of the cavities will be achieved by pumping with a set of cold compressors and warm vacuum pumps. While the L700 is already in operating, the 1.8 K system and the helium transfer system are in design phase.