Effects of the vibrations and electromagnetic pollution induced by a closed-cycle pulse-tube cryostat on...

A paradigm shift in achieving (sub-)Kelvin environments is currently underway with the democratization of cryogen-free cryocoolers. This transition is driven by their user-friendly, continuous operation and the elimination of liquid helium, which is becoming increasingly scarce and expensive. Thanks to their large sample space and high cooling power, these systems can host superconducting magnets, making them an ideal platform for quantum technologies, materials science, low-temperature detectors, and even medical applications. The drawback is that this type of system is inherently based on gas compression that induces a certain level of vibrations and electromagnetic perturbations, which can potentially prevent the determination of low amplitude signals or spoil their stability. In this paper, we demonstrate that pulse-tube based cryocoolers can be used for electrical precision measurements under a high magnetic field, using a commercial cryomagnetic system combined with a customized coaxial cryoprobe. A parts-per-billion level of measurement uncertainty in resistance determination, based on the quantum Hall resistance standard, is achievable, matching the state-of-the-art involving conventional cryostats based on liquid helium. We performed an extensive characterization of the cryomagnetic system to determine the levels of vibrations and electromagnetic perturbations, revealing the drastic effect of the magnetic field on the electromagnetic noise level. While interferences can occur in some measurements, others appear immune to the perturbations, meaning that the cryogen-free system is not inherently a source of disturbance. The set of characterization measurements presented here is easily implementable in laboratories, which can help to determine the vibrations and electromagnetic pollution generated by any cryocooler.