Cryogenic refrigeration requirements for superconducting insertion devices in a light source
This report discusses cryogenic cooling superconducting insertion devices for modern light sources. The introductory part of the report discusses the difference between wiggler and undulators and how the bore temperature may affect the performance of the magnets. The steps one would take to reduce the gap between the cold magnet pole are discussed. One section of the report is devoted to showing how one would calculate the heat that enters the device. Source of heat include, heat entering through the vacuum chamber, heating due to stray electrons and synchrotron radiation, heating due to image current on the bore, heat flow by conduction and radiation, and heat transfer into the cryostat through the magnet leads. A section of the report is devoted to cooling options such as small cryo-cooler and larger conventional helium refrigerators. This section contains a discussion as to when it is appropriate to use small coolers that do not have J-T circuits. Candidate small cryo-coolers are discussed in this section of the report. Cooling circuits for cooling with a conventional refrigerator are also discussed. A section of the report is devoted to vibration isolation and how this may affect how the cooling is attached to the device. Vibration isolation using straps is compared to vibration isolation using helium heat pipes. The vibration isolation of a conventional refrigeration system is also discussed. Finally, the cool down of an insertion device is discussed. The device can either be cooled down using liquid cryogenic nitrogen and liquid helium or by using the cooler used to keep the devices cold over the long haul.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Accelerator&Fusion Research Division; Advanced Light Source Division; Engineering Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 925747
- Report Number(s):
- LBNL-53578; TRN: US0802468
- Country of Publication:
- United States
- Language:
- English
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