Detalles de publicación
PP 09070
Planck pre-launch status: Design and description of the Low Frequency Instrument
1 Universit`a degli Studi di Milano, Dipartimento di Fisica, via Celoria 16, 20133 Milano, Italy (e-mail: marco.bersanelli@unimi.it) 2 INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, via Bassini 15, 20133 Milano, Italy 3 INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, via P. Gobetti, 101, I40129 Bologna, Italy 4 Universidad de Cantabria, Departamento de Ingenieria de Comunicaciones, av. de Los Castros s/n, 39005 Santander, Spain. 5 Thales Alenia Space Italia S.p.A., S.S. Padana Superiore 290, 20090 Vimodrone, Milano, Italy 6 SISSA/ISAS, Astrophysics Sector, Via Beirut 4, 34014 Trieste, Italy 7 CESR, Centre dEtude Spatiale des Rayonnements, 9, av du Colonel Roche, BP 44346 31028 Toulouse Cedex 4, France 8 Instituto de Fisica de Cantabria, CSIC, Universidad de Cantabria, av. de los Castros s/n, 39005 Santander, Spain 9 Jodrell Bank Centre for Astrophysics, Alan Turing Building, The University of Manchester, Manchester, M13 9PL, UK 10 Herschel/Planck Project, Scientific Projects Dpt of ESA, Keplerlaan 1, 2200 AG, Noordwijk, The Netherlands 11 Istituto di Fisica del Plasma, CNR, via Cozzi 53, 20125 Milano, Italy 12 ASI, Agenzia Spaziale Italiana, viale Liegi, 26, 00198 Roma, Italy 13 Dipartimento di Fisica, Universit`a degli Studi di Roma Tor Vergata, via della Ricerca Scientifica 1, 00133 Roma, Italy 14 INAF Osservatorio Astronomico di Padova, Vicolo dell Osservatorio 5, 35122 Padova, Italy 15 INAF Osservatorio Astronomico di Trieste, via Tiepolo, 11, I-34143 Trieste, Italy 16 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA 17 Instituto de Astrofisica de Canarias, C/ Via Lactea s/n, 38200, La Laguna, Tenerife, Spain 18 Dipartimento di Fisica, Universit`a degli Studi di Trieste, via A. Valerio 2, 34127 Trieste, Italy
In this paper we present the Low Frequency Instrument (LFI), designed and developed as part of the Planck space mission, the ESA program 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 di erential system using blackbody loads as reference signals. The front-end is cooled to 20K for optimal sensitivity and the reference loads are cooled to 4K 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 e ects. Further details on the key instrument units and the results of ground calibration are provided in a set of companion papers.