Operation of a high-Tc DC-SQUID-gradiometer on a non-metallic pulse tube refrigerator

Becker, Christoph; Steppke, Alexander; Koettig, T.; Gerster, J. A.; Dörrer, Lars; Thürk, M.; Schmidl, F.; Seidel, P.

doi:10.1088/1742-6596/97/1/012039

Cited by 5 publications

(3 citation statements)

References 19 publications

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“…This further indicates that the micro-cooler does not introduce significant magnetic fields in the vicinity of the cold stage that would enhance the 1/f magnetic flux noise of the SQUID. This is in contrast to high-T C SQUIDs operated with mechanical cryo-coolers where excessive low-frequency noise was clearly observed [24][25][26][27][28]. This noise is mainly due to the moving metallic parts, valves and mechanical vibrations of the cooler head that are difficult to eliminate.…”

Section: Discussionmentioning

confidence: 75%

“…This noise is mainly due to the moving metallic parts, valves and mechanical vibrations of the cooler head that are difficult to eliminate. A significant improvement of low-frequency noise could only be achieved with specially designed non-metallic pulse tube refrigerator [28]. Our micro-cooler is free from any metallic or moving parts and therefore does not contribute to the lowfrequency noise.…”

Section: Discussionmentioning

confidence: 99%

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

Kalabukhov

Hoon²,

Kuit³

et al. 2016

Supercond. Sci. Technol.

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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.

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

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

Kalabukhov

Hoon²,

Kuit³

et al. 2016

Supercond. Sci. Technol.

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“…These problems are major hurdles to the popularization of the SQUID system in clinical applications. Therefore, many research groups are attempting to develop a helium-free SQUID system [13][14][15][16][17][18][19], and have applied the superconductive shield to measure biomagnetic signals under a magnetically unshielded or a moderately shielded condition [20][21][22][23]. In the earlier cryocooled SQUID systems, the cold head is integrated with the SQUID sensor chamber to improve heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

Hung¹,

Lee²,

Lee³

et al. 2014

Supercond. Sci. Technol.

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We developed a cryocooled SQUID system with which human magnetocardiogram (MCG) and possibly magnetoenceparogram (MEG) can be measured. To reduce cyclic magnetic noises originating from the regenerator of the cold heads of the cryocooler, a superconductive shield (99.5% Pb) was used to protect the SQUID sensors, and a ferromagnetic shield (78% Ni alloy) was used to screen the cold head. In addition, the SQUID sensors' chamber was placed at a distance of 1.8 m from the cold head chamber to install the cold-head chamber outside the magnetically shielded room (MSR) for future development. The loss in cooling power due to the increased distance was compensated by increasing the number of thermal rods, and thus the SQUID sensor and superconductive shield could be refrigerated to 4.8 K and 5 K, respectively. The superconductive shield successfully rejected thermal noise emitted from metallic blocks used to improve thermal conduction. The noise of the SQUID system was 3 fT/Hz 1 2 , and the cyclic magnetic noise could be reduced to 1.7 pT. We could obtain a clear MCG signal while the entire cryogenics was in operation without any special digital processing.

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SQUIDsin Biomagnetism

Nowak

2015

Digital Encyclopedia of Applied Physics

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Operation of a high-Tc DC-SQUID-gradiometer on a non-metallic pulse tube refrigerator

Cited by 5 publications

References 19 publications

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

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

Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

SQUIDsin Biomagnetism

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Operation of a high-Tc DC-SQUID-gradiometer on a non-metallic pulse tube refrigerator

Cited by 5 publications

References 19 publications

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

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

Closed-cycle cryocooled SQUID system with superconductive shield for biomagnetism

SQUIDsin Biomagnetism

Contact Info

Product

Resources

About

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

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