The 45-m telescope is located at Nobeyama Radio Observatory (NRO) in Nagano, Japan and is one of the largest millimeter-wave telescopes in the world. The 45-m telescope is equipped with low-noise high electron mobility transistor (HEMT) and superconductor-insulator-superconductor (SIS) receivers covering the observing frequency range of 20 to 115 GHz, along with powerful spectral-line and continuum back-ends. Scientific discoveries using this instrument include the discovery of a super-massive black hole as well as finding of a number of interstellar molecules. These discoveries also cover a wide range of research fields, such as the formation of stars and planetary systems, the structure and activity of galaxies, and interstellar chemistry. The 100-GHz band SIS receivers are the most important ones for the 45-m telescope, because they cover the highest frequency range among the heterodyne SIS receivers installed in the telescope. From a scientific viewpoint, the J = 1-0 emission line of carbon monoxide (CO) in this frequency band is a principal probe for studies of interstellar molecular gas.
We have developed the waveguide-type dual-polarization sideband-separating (2SB) SIS receiver systems in 100-GHz band for this telescope. We are operating and/or developing three type new 100-GHz band receiver systems; single-beam receiver, two-beam receiver, and multi-beam receiver.
NRO 45-m millimeter wave telescope
Reference
Nakajima, T. et al., "A New 100-GHz Band Front-End System with a Waveguide-Type Dual-Polarization Sideband-Separating SIS Receiver for the NRO 45-m Radio Telescope", Publ. Astron. Soc. Japan 60, pp.435-443 (2008)
Nakajima, T., "Development of a New Multi-Beam Array 2SB Receiver in 100 GHz Band for the NRO 45-m Radio Telescope", Proc. of the 23rd International Symposium on Space Terahertz Technology, P-12, pp.1-4 (2012)
Nakajima, T. et al., "A New 100-GHz Band Two-Beam Sideband-Separating SIS Receiver for Z-Machine on the NRO 45-m Radio Telescope", Publ. Astron. Soc. Pacific 125, pp.252-262 (2013)