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TREND (Terahertz Receiver with NbN Device) is a terahertz heterodyne receiver system that was developed at the Terahertz Laboratory at UMass/Amherst by a group of scientists and students. TREND's team members also include scientists and students from UMass/Lowell, Chalmers University, University of Arizona, CalTech, and Harvard-Smithsonian Center for Astrophysics.
TREND represents the state-of-the art in sub-millimeter wave detection technology. TREND was succeesfully deployed at the AST/RO Telescope, South Pole Station, Antarctica during the austral summer of 2002-2003. The measured double-sideband noise temperature of the receiver is 1200 K at 1.27 THz.
The plateau of the South Pole is one of the best sites in the world for terahertz observation, based on its superior weather conditions. Figure 1 shows the transmission through the atmosphere at terahertz frequencies at the best conditions of the year (June 2001).
Figure 1. Opacity of the sky at terahertz frequencies at AST/RO (Richard Chamberlain, SAO).
Some astronomical goals of this instrument are:
- NII (1461.3 GHz) line is ubiquitous in the Warm Ionized Medium (WIM).
- CO J = 11 → 10 (1267.0 GHz) line is a promising probe for high excitation gas.
The heart of the receiver is a superconducting Hot Electron Bolometric (HEB) mixer receiver. HEB mixers operating above 1 THz have lower noise temperature compared with other available technologies such as SIS mixers or Shottky diode mixers (See Figure 2). HEB technology has become a very promising technology for heterodyne detection in the terahertz regime.
Figure 2. Comparision between different technologies for terahertz detection.
Created and mantained by frodrigu@ecs.umass.edu