COBRAS/SAMBA Low Frequency Instrument

COBRAS/SAMBA carries a Low Frequency Instrument (LFI) which is envisaged as coherent receivers using HEMT amplifiers. More information on the recievers can be found on the hardware information page. A block diagram of the LFI is shown in the next figure and summarized in the following table.

A major decision for the LFI performance is the question of active versus passive cooling. The instrument characteristics for passive cooling are well described in the Phase A Study "Red Book". Thus we show here more information on the active cooling appr

Block Diagram of Cooled LFI This figure shows a sketch of the configuration of the LFI for an actively cooled concept. The main spacecraft is at abou 300K, the payload instrument area (focal plane) is designed to be cooled passively via radiation to about 65 K. Active coolers can readily achieve a temperature of about 20K leading to a another factor of two improvement in sensitivity.

LFI Focal Plane Side View (Old)

LFI Focal Plane Top View (Old)

LFI Correlation Radiometer Concept