Project B7

Project leaders: Graf, Urs (PH1); Honingh, Netty (PH1)

Project B7 develops state-of-the-art receiver technology for high-resolution spectroscopy in astronomy. Velocity resolved spectroscopy is a key tool to study the physics of the interstellar gas. To provide the advanced instrumentation for these observations, we develop new heterodyne spectrometers for the submillimeter and Terahertz spectral range.

To complement the Low Frequency Array (LFA) of CHAI (CCAT-prime Heterodyne Array Instrument) we will develop the High Frequency Array HFA, an 8×8 pixel focal plane array for frequencies around 800 GHz.

An important technology development will be to build on-chip sideband separating (2SB) mixers to achieve better sensitivity under difficult atmospheric conditions and to simplify the identification of spectral lines. This effort, from the very beginning, aims at reaching large IF bandwidths for efficient frequency coverage.

We will also develop SIS mixers for frequencies beyond 1 THz. The FYST telescope is currently the most promising instrument for ground based observations of the important [N II] transition at 1.5 THz.

References

  1. Büchel, Pütz, Jacobs, Schultz, Graf, Risacher, Richter, Ricken, et al., “4.7-THz Superconducting Hot Electron Bolometer Waveguide Mixer”, IEEE Transactions on Terahertz Science and Technology 5, 207 (2015).
  2. Graf and Heyminck, “Fourier gratings as submillimeter beam splitters”, IEEE Transactions on Antennas and Propagation 49, 542 (2001).
  3. Graf, Heyminck, Michael, Stanko, Honingh, Jacobs, Schieder, Stutzki, et al., “SMART: The KOSMA Sub-Millimeter Array Receiver for Two frequencies”, Proceedings of the SPIE 4855, edited by Phillips and Zmuidzinas, 322 (2003).
  4. Graf, Honingh, Jacobs, and Stutzki, “Terahertz Heterodyne Array Receivers for Astronomy”, Journal of Infrared, Millimeter, and Terahertz Waves 36, 896 (2015).
  5. Groppi, Baryshev, Graf, Wiedner, Klaassen, and Mroczkowski, “First Generation Heterodyne Instrumentation Concepts for the Atacama Large Aperture Submillimeter Telescope”, Proceedings of the ISSTT 30 (2019).
  6. Heyminck, Graf, Güsten, Stutzki, Hübers, and Hartogh, “GREAT: the SOFIA high-frequency heterodyne instrument”, A&A 542, L1 (2012).
  7. Lüthi, Rabanus, Graf, Granet, and Murk, “Expandable fully reflective focal-plane optics for millimeter- and submillimeter-wave array receivers”, Review of Scientific Instruments 77, 4702 (2006).
  8. Risacher, Güsten, Stutzki, Hübers, Büchel, Graf, Heyminck, Honingh, et al., “First Supra-THz Heterodyne Array Receivers for Astronomy With the SOFIA Observatory”, IEEE Transactions on Terahertz Science and Technology 6, 199 (2016).
  9. Westig, Justen, Jacobs, Stutzki, Schultz, Schomacker, and Honingh, “A 490 GHz planar circuit balanced Nb–Al2O3–Nb quasiparticle mixer for radio astronomy: Application to quantitative local oscillator noise determination”, Journal of Applied Physics 112, 093919 (2012).