학술논문
The upGREAT dual frequency heterodyne arrays for SOFIA
Document Type
Working Paper
Author
Risacher, C.; Güsten, R.; Stutzk, J.; Hübers, H. -W.; Aladro, R.; Bell, A.; Buchbender, C.; Büchel, D.; Csengeri, T.; Duran, C.; Graf, U. U.; Higgins, R. D.; Honingh, C. E.; Jacobs, K.; Justen, M.; Klein, B.; Mertens, M.; Okada, Y.; Parikka, A.; Pütz, P.; Reyes, N.; Richter, H.; Ricken, O.; Riquelme, D.; Rothbart, N.; Schneider, N.; Simon, R.; Wienold, M.; Wiesemeyer, H.; Ziebart, M.; Fusco, P.; Rosner, S.; Wohler, B.
Source
Subject
Language
Abstract
We present the performance of the upGREAT heterodyne array receivers on the SOFIA telescope after several years of operations. This instrument is a multi-pixel high resolution (R > 10^7) spectrometer for the Stratospheric Observatory for Far-Infrared Astronomy (SOFIA). The receivers use 7-pixel subarrays configured in a hexagonal layout around a central pixel. The low frequency array receiver (LFA) has 2x7 pixels (dual polarization), and presently covers the 1.83-2.06 THz frequency range, which allows to observe the [CII] and [OI] lines at 158 um and 145 um wavelengths. The high frequency array (HFA) covers the [OI] line at 63 um and is equipped with one polarization at the moment (7 pixels, which can be upgraded in the near future with a second polarization array). The 4.7 THz array has successfully flown using two separate quantum-cascade laser local oscillators from two different groups. NASA completed the development, integration and testing of a dual-channel closed-cycle cryocooler system, with two independently operable He compressors, aboard SOFIA in early 2017 and since then, both arrays can be operated in parallel using a frequency separating dichroic mirror. This configuration is now the prime GREAT configuration and has been added to SOFIA's instrument suite since observing cycle 6.
Comment: Accepted to the Journal of Astronomical Instrumentation (SOFIA Special Edition) on 12th November 2018
Comment: Accepted to the Journal of Astronomical Instrumentation (SOFIA Special Edition) on 12th November 2018