Records |
Author |
Meledin, Denis; Pavolotsky, Alexey; Desmaris, Vincent.; Lapkin, Igor; Risacher, Christophe; Perez, Victor; Henke, Douglas; Nystrom, Olle; Sundin, Erik; Dochev, Dimitar; Pantaleev, Miroslav; Fredrixon, Mathias; Strandberg, Magnus; Voronov, Boris; Goltsman, Gregory; Belitsky, Victor |
Title |
A 1.3-THz balanced waveguide HEB mixer for the APEX telescope |
Type |
Journal Article |
Year |
2009 |
Publication |
IEEE Trans. Microw. Theory Techn. |
Abbreviated Journal |
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Volume |
57 |
Issue |
1 |
Pages |
89-98 |
Keywords |
HEB, mixer, waveguide, balanced, NbN |
Abstract |
In this paper, we report about the development, fabrication, and characterization of a balanced waveguide hot electron bolometer (HEB) receiver for the Atacama Pathfinder EXperiment telescope covering the frequency band of 1.25–1.39 THz. The receiver uses a quadrature balanced scheme and two HEB mixers, fabricated from 4- to 5-nm-thick NbN film deposited on crystalline quartz substrate with an MgO buffer layer in between. We employed a novel micromachining method to produce all-metal waveguide parts at submicrometer accuracy (the main-mode waveguide dimensions are 90×180 μm). We present details on the mixer design and measurement results, including receiver noise performance, stability and “first-light†at the telescope site. The receiver yields a double-sideband noise temperature averaged over the RF band below 1200 K, and outstanding stability with a spectroscopic Allan time more than 200 s. |
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0018-9480 |
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RPLAB @ lobanovyury @ |
Serial |
554 |
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Author |
Samsonova, Alena; Zolotov, Philipp; Baeva, Elmira; Lomakin, Andrey; Titova, Nadezhda; Kardakova, Anna; Goltsman, Gregory |
Title |
Signatures of surface magnetic disorder in thin niobium films |
Type |
Journal Article |
Year |
2021 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
1-1 |
Keywords |
Temperature measurement, Temperature dependence, Superconducting magnets, Superconducting transition temperature, Substrates, Resistance, Scattering |
Abstract |
We present our studies on the evolution of the normal and superconducting properties with thickness of thin Nb films with a low level of non-magnetic disorder (kFl 150 for the thickest film in the set). The analysis of the superconducting behavior points to the presence of magnetic moments, hidden in the native oxide on the surface of Nb films. Using the Abrikosov-Gorkov theory, we obtain the density of surface magnetic moments of 1013 cm-2, which is in agreement with the previously reported data for Nb films. |
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1051-8223 |
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Call Number |
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Serial |
1162 |
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