An ultrahigh-vacuum nitrogen-free helium cryostat with small heat losses

Trofimov, V. N.; Chernikov, A. N.; Zaĭtsev-Zotov, S. V.; Dyuzhikov, I. N.; Shevlyuga, V. M.; Eltsov, K. N.

doi:10.1134/s002044120706022x

Cited by 5 publications

(2 citation statements)

References 6 publications

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“…Closed-cycle helium refrigerators are self-contained and easy to use, but they are prone to large temperature gradients and mechanical instability produced by a compressor and the cooling system itself, making them unsuitable for strict temperature-dependent measurements or for measuring small samples [ 13 , 14 ]. Bath (or immersion) cryostats provide optimum temperature and mechanical stability while providing a large-caliber cryogenic space for optical experiments without high loss of liquid helium [ 15 , 16 ]. Cryostats filled with liquid coolants are quite compatible with ultra-high vacuum equipment, including magnets.…”

Section: Introductionmentioning

confidence: 99%

A Cryostat Applicable to Long-Wavelength Light-Driven Scanning Probe Microscopy

et al. 2023

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Recently, there has been growing interest in using lightwave-driven scanning probe microscopy (LD-SPM) to break through the Abbe diffraction limit of focusing, yielding insight into various energy couplings and conversion processes and revealing the internal information of matter. We describe a compact and efficient optical cryostat designed for LD-SPM testing under magnetic fields. The exceptional multilayer radiation shielding insert (MRSI) forms an excellent temperature gradient when filled with heat conducting gas, which removes the requirement to install an optical window in the liquid helium cooling shell. This not only critically avoids the vibration and thermal drift caused by solid heat conduction but also minimizes light transmission loss. The application of gate valves and bellows allows a simpler and more effective replacement of the sample and working cell in the test cavity. ANSYS software is used for steady-state thermal analysis of the MRSI to obtain the temperature distribution and heat transfer rate, and the necessity of the flexible copper shielding strips is illustrated by the simulations. The topography and magnetic domain images of 45 nm-thick La0.67Ca0.33MnO3 thin films on NdGaO3(001) substrates under a magnetic field were obtained by a self-made lightwave-driven magnetic force microscope in this cryostat. The resolution and noise spectra during imaging reveal temperature stability and low vibration throughout the cryostat. The experience acquired during the development of this cryostat will help to establish cryostats of similar types for a variety of optic applications requiring the use of cryogenic temperatures.

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Section: Introductionmentioning

confidence: 99%

A Cryostat Applicable to Long-Wavelength Light-Driven Scanning Probe Microscopy

et al. 2023

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“…In the past decades, the severe shortage of helium [3] has made it increasingly difficult to conduct low-temperature scanning probe microscopy (SPM) experiments. While the use of low helium boil-off cryostats [4][5][6] can alleviate the problem, the ultimate solution lies in the integration of a cryogen-free refrigerator into the SPM system itself. Such integration would not only eliminate the dependency on scarce helium, but it would also enable experiments to be carried out uninterrupted without the need for cryogen refills.…”

Section: Introductionmentioning

confidence: 99%

Development of a near-5-Kelvin, cryogen-free, pulse-tube refrigerator-based scanning probe microscope

Kasai,

Koyama,

Yokota

et al. 2022

Preprint

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We report the design and performance of a cryogen-free, pulse-tube refrigerator (PTR)-based scanning probe microscopy (SPM) system capable of operating at the base temperature of near 5 K. We achieve this by combining a home-made interface design between the PTR cold head and the SPM head, with an automatic gas-handling system. The interface design isolates the PTR vibrations by a combination of polytetrafluoroethylene and stainless-steel bellows, and by placing the SPM head on a passive vibration isolation table via two cold stages that are connected to thermal radiation shields using copper heat links.The gas-handling system regulates the helium heat-exchange gas pressures, facilitating both the cool down to and the maintenance of the base temperature. We discuss the effects of each component using measured vibration, current-noise, temperature, and pressure data. We demonstrate that our SPM system performance is comparable to known liquid-helium-based systems with the measurements of the superconducting gap spectrum of Pb, atomic-resolution scanning tunneling microscopy image and quasiparticle interference pattern of Au(111) surface, and non-contact atomic force microscopy image of NaCl(100) surface. Without the need for cryogen refills, the current SPM system enables uninterrupted low-temperature measurements.

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Development of a near-5-Kelvin, cryogen-free, pulse-tube refrigerator-based scanning probe microscope

Kasai¹,

Koyama²,

Yokota³

et al. 2022

Review of Scientific Instruments

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We report the design and performance of a cryogen-free, pulse-tube refrigerator (PTR)-based scanning probe microscopy (SPM) system capable of operating at a base temperature of near 5 K. We achieve this by combining a home-made interface design between the PTR cold head and the SPM head, with an automatic gas-handling system. The interface design isolates the PTR vibrations by a combination of polytetrafluoroethylene and stainless-steel bellows and by placing the SPM head on a passive vibration isolation table via two cold stages that are connected to thermal radiation shields using copper heat links. The gas-handling system regulates the helium heat-exchange gas pressures, facilitating both the cooldown to and maintenance of the base temperature. We discuss the effects of each component using measured vibration, current-noise, temperature, and pressure data. We demonstrate that our SPM system performance is comparable to known liquid-helium-based systems with the measurements of the superconducting gap spectrum of Pb, atomic-resolution scanning tunneling microscopy image and quasiparticle interference pattern of Au(111) surface, and non-contact atomic force microscopy image of NaCl(100) surface. Without the need for cryogen refills, the present SPM system enables uninterrupted low-temperature measurements.

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An ultrahigh-vacuum nitrogen-free helium cryostat with small heat losses

Cited by 5 publications

References 6 publications

A Cryostat Applicable to Long-Wavelength Light-Driven Scanning Probe Microscopy

A Cryostat Applicable to Long-Wavelength Light-Driven Scanning Probe Microscopy

Development of a near-5-Kelvin, cryogen-free, pulse-tube refrigerator-based scanning probe microscope

Development of a near-5-Kelvin, cryogen-free, pulse-tube refrigerator-based scanning probe microscope

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