Temperature detection circuit on the low-temperature superconducting coils

摘要

Experimental Advanced Superconducting Tokamak(EAST) is the fully superconducting Tokamak.The EAST magnet system comprises 16 D-shaped toroidal field coils and 14 poloidal field coils which are cooled by supercritical helium at 4.2 K and 3.8 K.The temperature of superconducting coils is measured by Cernox as a new type low-temperature sensor,and monitored during the cooling and operation.The helium temperature can offer reference for quench signal.In this paper,a technique for the weak temperature signal measurement of superconducting coils is introduced,and its weak voltage is extracted from the intrinsic noise of the amplifier by the low-noise instrumentation amplifier,filter circuit,and high-linearity analog optocoupler.The temperature detection circuit works accurately and safely whether in cooling or operating process.This technique is an effective for the temperature detection on the low-temperature superconducting coils.