DEVELOPMENT OF COOLING SYSTEM FOR CRYOGENIC PREAMPLIFIER IN FT-ICR ION TRAP

The cooling system of cryogenic preamplifier was designed and fabricated for Fourier transform ion cyclotron resonance (FT-ICR) ion trap. A cryogenic preamplifier consisted of non-magnetic materials is thermally connected to the cooling medium which is passing through the flange maintaining ultra-high vacuum in the ion cell. At the other end, the cooling medium is thermally anchored to the coldhead of cryocooler (conduction-cooled system) or liquid helium (liquid circulation system). In the conduction-cooled system the temperature distribution along the cooling medium was calculated by the relevant thermal analysis for steady-state. The liquid circulation unit with cryogenic preamplifier was installed in 7 T FT-ICR system and the temperature at the preamplifier was measured during the initial cool-down process. The effects of thermal radiation, contact resistance, and magnetic field on the temperature distribution were also investigated.