Cryogenic design of KOSMA's SOFIA Terahertz Array Receiver (STAR)
Abstract
We present the opto-mechanical layout of KOSMA's (Kölner Observatorium für SubMillimeter Astronomie) submillimeter and terahertz heterodyne array receiver STAR (SOFIA Terahertz Array Receiver) which is derived from SMART (Sub-Millimeter Array Receiver for Two frequencies). To reduce the alignment effort, SMART, for the first time, uses an integrated optics concept with no adjustable optical components inside the receiver dewar. For STAR this successful design concept will be extended and adapted for 1.9 THz and for use aboard SOFIA (Stratospheric Observatory For Infrared Astronomy). The design of STAR's cryostat and cryogenic optics is described. Emphasis is laid on the required accuracy for 4x4 spatially multiplexed Terahertz heterodyne receivers. The proposed design of the local oscillator, a frequency-tripled BWO (Backward Wave Oscillator), is outlined. The presentation comprises the scheme for multiplexing the local oscillator, dense arrangement of mixer elements in a cryogenic focal plane and manufacturing techniques of integrated optics units for reduction of optical adjustment efforts in astronomical submillimeter and terahertz receivers.
- Publication:
-
Z-Spec: a broadband millimeter-wave grating spectrometer: design, construction, and first cryogenic measurements
- Pub Date:
- October 2004
- DOI:
- 10.1117/12.551311
- Bibcode:
- 2004SPIE.5498..473R