Key Technologies for Liquid Helium solutions of Cryogenic Systems

      Helium resource is finite and decreasing rapidly now days. Helium users face periodic helium shortages as well as high and continuously increased helium prices.   Liquid helium free (dry) or zero boil off (ZBO) systems, such as SQUIDs system, DR, ADR, SC magnet and STM, etc., become more and more popular.  This talk will introduce key technologies using for these cryogenic systems, which include:
1.Background Introduction: helium resource and liquid helium solutions with 4 K cryocoolers.
2.Working principle of GM and pulse tube cryocoolers.
3.GM and pulse tube cryocoolers operating below 4 K.
4.Compact 2 K cryocooler development
5.Enable technologies for cryocooler integration: vibration and vibration damping; temperature oscillation and temperature damping, magnetic distortion and free intermediate precooling at 4-20K from pulse tube cryocooler.
6.Examples of some systems in the low temperature range of 0.01 K to 4K.