The Herschel-Heterodyne Instrument for the Far-Infrared (HIFI): instrument and pre-launch testing

Abstract

This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI), to be launched onboard of ESA's Herschel Space Observatory, by 2008. It includes the first results from the instrument level tests. The instrument is designed to be electronically tuneable over a wide and continuous frequency range in the Far Infrared, with velocity resolutions better than 0.1 km/s with a high sensitivity. This will enable detailed investigations of a wide variety of astronomical sources, ranging from solar system objects, star formation regions to nuclei of galaxies. The instrument comprises 5 frequency bands covering 480-1150 GHz with SIS mixers and a sixth dual frequency band, for the 1410-1910 GHz range, with Hot Electron Bolometer Mixers (HEB). The Local Oscillator (LO) subsystem consists of a dedicated Ka-band synthesizer followed by 7 times 2 chains of frequency multipliers, 2 chains for each frequency band. A pair of Auto-Correlators and a pair of Acousto-Optic spectrometers process the two IF signals from the dual-polarization front-ends to provide instantaneous frequency coverage of 4 GHz, with a set of resolutions (140 kHz to 1 MHz), better than < 0.1 km/s. After a successful qualification program, the flight instrument was delivered and entered the testing phase at satellite level. We will also report on the pre-flight test and calibration results together with the expected in-flight performance.

Design and first-light performance of TES bolometer arrays for submillimeter spectroscopy with ZEUS-2

“…We use telluric transmission models with 0.5 mm and 0.72 mm PWV for APEX and CSO (at band center) respectively-appropriate for good submillimeter nights at their sites (APEX windows < 300 μm use 0.2 mm). Also plotted is the sensitivity of ZEUS, the published preflight sensitivities of the 3 spectrometers on the Herschel telescope 16,17,18 with HIFI and PACS scaled to the resolving power of ZEUS-2: R = 1000, or Δυ = 300 km s -1 , appropriate for typical extragalactic line widths. ZEUS-2 is ~10 times more sensitive in the primary bands.…”

ZEUS-2: a second generation submillimeter grating spectrometer for exploring distant galaxies

“…We use telluric transmission models with 0.5 mm and 0.72 mm PWV for APEX and CSO (at band center) respectivelyappropriate for good submillimeter nights at their sites (APEX windows < 300 μm use 0.2 mm). Also plotted is the sensitivity of ZEUS, the published preflight sensitivities of the 3 spectrometers on the Herschel telescope 33,34,35 with HIFI and PACS scaled to the resolving power of ZEUS-2: R = 1000, or Δυ = 300 km s -1 , appropriate for typical extragalactic line widths. ZEUS-2 is ~10 times more sensitive in the primary bands.…”

Celestial Signals: Are Low-Noise Amplifiers the Future for Millimeter-Wave Radio Astronomy Receivers?

“…SOFIA [14], or in space, e.g. Herschel HIFI instrument [15]. Astronomers were thus provided with a detection tool of unparalleled sensitivity and that has gain substantial maturity through the outstanding work of numerous researchers and their institutes.…”