Operation of a high-T_CSQUID gradiometer with a two-stage MEMS-based Joule–Thomson micro-cooler

Abstract

Practical applications of high-TC superconducting quantum interference devices (SQUIDs) require cheap, simple in operation, and cryogen-free cooling. Mechanical cryo-coolers are generally not suitable for operation with SQUIDs due to their inherent magnetic and vibrational noise. In this work, we utilized a commercial Joule–Thomson microfluidic two-stage cooling system with base temperature of 75 K. We achieved successful operation of a bicrystal high-TC SQUID gradiometer in shielded magnetic environment. The micro-cooler head contains neither moving nor magnetic parts, and thus does not affect magnetic flux noise of the SQUID even at low frequencies. Our results demonstrate that such a microfluidic cooling system is a promising technology for cooling of high-TC SQUIDs in practical applications such as magnetic bioassays.

Volume-amplified magnetic bioassay integrated with microfluidic sample handling and high-Tc SQUID magnetic readout

“…One of the drawbacks is the need for low temperature to operate our high- T c SQUIDs. Recently, we have demonstrated the successful operation and noise measurements of a high- T c SQUID utilizing a commercial two stage micro-electromechanical system (MEMS) based Joule-Thomson micro-cooler, CryoLab from Kryoz Technologies BV (Kalabukhov et al , 2016). The micro-cooler offers a long operation time, simple usage, and temperature stability and adjustment.…”

Progress in and Outlook for Cryogenic Microcooling

“…Further optimization of the open-cycle microcooling system includes the elimination of additional wire resistance and electromagnetic interference from the miniature membrane pump in the control unit. Moreover, the gas cylinder in the open-cycle loop is expected to be replaced by a miniature gas compressor in order to realize a closed-cycle microcooling system [9].…”

“…Electronic devices, such as CMOS Si electronics [1,2], GaAs-based low-noise amplifiers [3], infrared detectors [4], and x-ray detectors [5], could benefit from operating at cryogenic temperatures in several forms: higher speed, higher signal-to-noise ratio, larger bandwidth, improved sensitivity [6]. Cryogenic temperatures also can offer some unique capabilities to superconducting devices [7][8][9], which are not available at ambient temperature. Besides electronic devices, experimental research on temperature-dependent properties, such as resistance, Seebeck coefficient, mobility, impurity distribution, etc [10], also requires cryogenic temperatures.…”

High-TcSQUID biomagnetometers

“…However, cryogen transfer and cryostat costs are less critical for high-T c systems when compared to low-T c systems, as suggested in [42]. Cryogen-free cooling systems (see, e.g., [43]) can also be used, provided that their magnetic noise is sufficiently low.…”