The Local Oscillator System for the Heterodyne Instrument for FIRST (HIFI)

摘要

The Heterodyne Instrument for FIRST (HIFI) is comprised of five SIS receiver channels covering 480-1250 GHz and two HEB receiver channels covering parts of 1410-1910 GHz and 2400-2700 GHz. Two local oscillator sub-bands derived from a common synthesizer will pump each receiver band. The synthesizer, control electronics and frequency distribution will be performed in the spacecraft service module. The service module will be connected to the local oscillator unit ont he outside of the cryostat with a WR-28 waveguide for each of the 14 local oscilator sub-bands. The local oscillator unit will be passively cooled and thermally isolated from the crystat wall. The module is comprised of seven units, oone for each receiver band, containing two multiplier chains consisting of a k-to w-band multiplier, a MMIC power amplifier operating in one of five bands between 71 and 113 GHz, the high frequency multipliers, launching optics and electrical distribution. The entire assembly will be cooled to 120K. The local oscillator system has the two fold technical challenge of providing broad band frequency coverage at very high frequencies. This will be achieved through the use of high power GaAs MMIC amplifiers and planar diode multiplier technology in a passively cooled 120 Kelvin environment. The design criteria and the resulting overall system design will be presented along with a programmatic view of the development program and development progress.