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@INPROCEEDINGS{Visser:1037143,
      author       = {Visser, Lino and Neis, Marc and Guimaraes, Jeferson R. and
                      Jerger, Markus and Bushev, Pavel and Barends, Rami and
                      Mourik, Vincent},
      title        = {{T}wo-stage magnetic shielding for hybrid quantum devices
                      in an adiabatic demagnetization refrigerator},
      reportid     = {FZJ-2025-00490},
      year         = {2024},
      abstract     = {Adiabatic demagnetization refrigeration (ADR) is a
                      promising cooling technique 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 is the
                      presence residual magnetic fields originating from the
                      magnet used for recharging the paramagnetic salts, as these
                      lower the operation fidelity of superconducting
                      circuits.With the advance of spin qubits and the recent
                      demonstration of long-range coupling by superconducting
                      resonators[1,2], controlling the magnetic environment is
                      crucial. Further, controlling this is beneficial to operate
                      spin qubits at low fields[3] or to implement
                      superconducting-semiconducting hybrid devices in Germanium
                      quantum wells[4,5].Here, we present the design of a 4 Kelvin
                      two-stage mu-metal and Niobium magnetic shield[6] with ports
                      for 4 superconducting RF wires, and 48 DC lines. The lowest
                      temperature stage enters the magnetic shield through a
                      feedthrough and contains an additional Copper radiation
                      shield[7] 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 factors. First results indicate a
                      competitive performance of these resonators in our
                      customized set-up. To operate spin qubits, we plan on
                      implementing a small superconducting magnet to control the
                      field locally. We aim to achieve a reduced background field,
                      magnetic field noise and avoid field exposure while
                      recharging the salt pill. [1] P. Harvey-Collard et al. Phys.
                      Rev. X 12, 021026[2] F. Borjans et al. Nature 577, 195–198
                      (2020)[3] D Jirovec et al. Nat. Mater. 20, 1106–1112
                      (2021)[4] O. Sagi et al. arXiv:2403.16774[5] A. Tosato et
                      al. Commun Mater 4, 23 (2023)[6] A. Bergen et al. Rev Sci
                      Instrum. 2016 Oct;87(10):105109[7] R. Barends et al. Appl.
                      Phys. Lett. 99, 113507 (2011)},
      month         = {Sep},
      date          = {2024-09-04},
      organization  = {Silicon Quantum Electronics Workshop
                       2024, Davos (Switzerland), 4 Sep 2024 -
                       6 Sep 2024},
      subtyp        = {After Call},
      cin          = {PGI-11},
      cid          = {I:(DE-Juel1)PGI-11-20170113},
      pnm          = {5221 - Advanced Solid-State Qubits and Qubit Systems
                      (POF4-522) / EXC 2004:  Matter and Light for Quantum
                      Computing (ML4Q) (390534769)},
      pid          = {G:(DE-HGF)POF4-5221 / G:(BMBF)390534769},
      typ          = {PUB:(DE-HGF)24},
      doi          = {10.34734/FZJ-2025-00490},
      url          = {https://juser.fz-juelich.de/record/1037143},
}