Berlin 2024 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 18: Superconductivity: Poster

TT 18.70: Poster

Monday, March 18, 2024, 15:00–18:00, Poster C

Two-stage magnetic shielding for superconducting circuits in an adiabatic demagnetization refrigerator — •Lino Visser¹, Marc Neis², Jéferson Guimarães², Markus Jerger², Pavel Bushev², Vincent Mourik¹, and Rami Barends² — ¹JARA-Fit Institute for Quantum Information, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany — ²Peter Grünberg Institut 13 Institute for Functional Quantum Systems, Forschungszentrum Jülich GmbH, Jülich, Germany

Adiabatic demagnetization refrigeration (ADR) is a promising technology for future quantum technology applications. Cooling units for ADRs are cheap and reliable while enabling base temperatures comparable to those obtained in dilution refrigerators. A challenge are the residual magnetic fields originating from the magnet used for recharging the paramagnetic salts, as these lower the operation fidelity of superconducting circuits. Here, we present the design of a 4 Kelvin two-stage mu-metal and Niobium magnetic shield with ports for 4 RF wires, and 48 DC lines. The lowest temperature stage enters the magnetic shield through a feedthrough, and contains an additional Copper infrared shield around the sample space. Using finite element simulations, we quantify the magnetic shielding factor before manufacturing. To benchmark the ADRs shielding performance, we characterize a set of Niobium resonators, measuring their quality factor. First results indicate a competitive performance of these resonators in our customized set-up.

Keywords: Superconducting resonator; Magnetic shielding