The APEX-2A receiver specifications
|
RF tuning range |
282-378 GHz (possibilities to extend this range by careful manual tuning down to 279 GHz and up to 381 GHz). |
IF frequency |
Centered at 6 GHz. IF bandwidth is 4-8 GHz |
Noise temperature |
40 ± 15 K (DSB) across RF band. Corresponds to 2-3 quantum noise. |
Optics |
Flat and active cold mirrors + 9 warm mirrors to obtain a beamwaist of 6 mm to match the APEX Cassegrain waist |
Cryogenics |
Old SEST SESIS cryostat. Closed cycle cooling system. 1 compressor CTI 8500 with cold head CTI1020 to produce 80K and 12K. 1 compressor Quantum J20 for 4K stage. Cooling time of 14hours. |
Calibration |
External closed-cycle calibration unit in Cabin A providing 73 K for cold load and about 288 K for the hot load. |
Computer control |
Control system using National Instrument Fieldpoint modules. Ethernet connection to the telescope network. Virtually possible to tune from anywhere. |
Tuning |
Tuneless mixer. A full automatic tuning procedure takes less than 3 minutes to tune the receiver. Manual tuning is possible to optimize further for stability or reach the edges of the receiver band. |