Hi All, I need some basic info of He closed cycle cryos..(like working principle, etc).. I have a compressor, which compress He gas and passed in to a cryo's coldhead. So He gas expands in side the coldhead and cools the coldhead..then it again passes in to compressor..so the cycle repeats.. I just want to know why and how vibrations are produced in such cryo (i.e., in coldhead) ? [The compressor and coldhead are connected via tube, so i think vibrations are not from compressor!] Is there any clever way to damp these vibrations ?? If i am correct there are no moving parts in coldhead !!!!? Does any have some schematic sketch of coldhead or cross section of a coldhead..i searched the internet..but dint get any idea!!! or what is inside coldhead.. thanks for your help Rajini.