2-02
Sergey Cherednichenko, J.R. Gao
Chalmers University of Technology
Reducing cryogenic requirements of THz heterodyne receivers using MgB2 HEB mixer technology
Superconducting Hot-Electron Bolometer (HEB) mixers have proven to meet demanding requirements of Terahertz Astronomy in a number of heterodyne instruments, including SOFIA (GREAT and up-Great), Heschel (HIFI), APEX, STO2). Also, arrays of order of 10 HEB mixers have been deployed or developed (upGREAT, GUSTO). HEB mixers based on NbN or NbTiN require an operating temperature down to 4K, hence being forced to use either liquid helium or bulky, high power 4K coolers. During the recent years a new material concept for HEBs has risen, utilizing magnesium diboride (MgB2). With a critical temperature close to 40K, MgB2 HEBs have shown sensitivities being competitive to its low critical temperature counterparts (NbN) across the entire THz range (0.7 THz, 1.6THz, 2.5THz, and very recently at 5.3THz). Interestingly, such THz mixers have demonstrated operation up to 30 K, hence allowing for much more compact stirling coolers, which have been space qualified. It can reduced the cost and complicity of instruments significantly. It may also extend the mission life time, hence maximizing its scientific return. Furthermore, the intermediate frequency (IF) bandwidth is increased by a factor of more than 3, exceeding 10GHz. In our presentation we will give an overview of possible concepts for THz heterodyne receivers for SOFIA and an M-class FIR mission recommended by ESA voyage 2050 Senior Committee by taking advantage of the MgB2 HEB technology.
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