First operation of the XFEL linac with the 2 K cryogenic system

Cryogenic Engineering Conference 2017

材料科学;物理学

Paetzold, T.^2 ; Petersen, B.^1 ; Schnautz, T.^1 ; Ueresin, C.^1 ; Zajac, J.^3

Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany^1

Lindekryotechnik/Engie, Hamburg, Germany^2

Lindekryotechnik, Pfungen, Switzerland^3

关键词: Cold compressors;    Control valves;    Cryogenic system;    Dynamic heat;    Flow bypass;    Helium II;    Helium vapor;    Mass flow;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/278/1/012101/pdf
DOI  :  10.1088/1757-899X/278/1/012101

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The RF operation of the about 800 superconducting 1.3 GHz 9-cell cavities of the XFEL linac requires helium II bath cooling at 2 K, corresponding to a vapor pressure of 3100 Pa. After the first cool-down of the XFEL linac to 4 K in December, 27th2016 the operation of the 2 K cryogenic system was started in January, 2nd2017. The 2 K cryogenic system consist of a 4-stage set of cold compressors to compress helium vapor at a mass flow of up to 100 g/s from 2400 Pa to about 110 kPa and a full flow bypass with an arrangement of heat exchangers and control valves. This paper describes the XFEL refrigerating plant, especially the 2 K cryogenic system, the tuning of the cold compressor regulation to adapt to the XFEL linac static and dynamic heat loads and experience of about 6 months of operation.