Planck pre-launch status: Design and description of the Low Frequency Instrument

M. Bersanelli, N. Mandolesi, R.C. Butler, Jussi Tuovinen, Jussi Varis, et al.

    Research output: Contribution to journalArticleScientificpeer-review

    125 Citations (Scopus)

    Abstract

    In this paper we present the Low Frequency Instrument (LFI), designed and developed as part of the Planck space mission, the ESA programme dedicated to precision imaging of the cosmic microwave background (CMB). Planck-LFI will observe the full sky in intensity and polarisation in three frequency bands centred at 30, 44 and 70 GHz, while higher frequencies (100–850 GHz) will be covered by the HFI instrument. The LFI is an array of microwave radiometers based on state-of-the-art indium phosphide cryogenic HEMT amplifiers implemented in a differential system using blackbody loads as reference signals. The front end is cooled to 20 K for optimal sensitivity and the reference loads are cooled to 4 K to minimise low-frequency noise. We provide an overview of the LFI, discuss the leading scientific requirements, and describe the design solutions adopted for the various hardware subsystems. The main drivers of the radiometric, optical, and thermal design are discussed, including the stringent requirements on sensitivity, stability, and rejection of systematic effects. Further details on the key instrument units and the results of ground calibration are provided in a set of companion papers.
    Original languageEnglish
    Number of pages21
    JournalAstronomy and Astrophysics
    Volume520
    DOIs
    Publication statusPublished - 2010
    MoE publication typeA1 Journal article-refereed

    Keywords

    • cosmic microwave background – telescopes – space vehicles: instruments – instrumentation
    • detectors – instrumentation
    • polarimeters – submillimeter
    • general

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