2005 Volume 40 Issue 7 Pages 300-304
A high-Tc superconducting quantum interference device(HTS SQUID)cooling system was developed based on a pulse-tube cryocooler (PTC) and a novel temperature controller. In this system, the temperature controller uses infrared irradiation instead of the commonly employed electric heater to provide accurate and low-noise performances. The infrared light was irradiated via a fiber-optic cable onto a SQUID-mount stage, where a HTS SQUID was cooled to approximately 77 K by the PTC. The output of the irradiation source was controlled with a feedback scheme while monitoring the temperature of the SQUID-mount stage. The temperature of the stage was stabilized at 77 K, and kept within ±0.03 K deviation, for more than 2 hr by the temperature controller. The measured magnetic flux noise of the HTS SQUID magnetometer in the cooling system with the temperature controller showed little magnetic influence due to infrared irradiation.
