HIFI The Heterodyne Instrument for the Far Infrared
A very high resolution spectrometer covering 480 - 1910 GHz (625 - 157 µm)

Rendition of the HIFI Focal Plane Unit (FPU)	The HIFI FPU Qualifcation Module prepared for cold vibration tests, CSL (Liège), Summer 2005.

Introduction

Principal Investigator: Thijs de Graauw, Netherlands Institute for Space Research Co-Principal Investigators: Tom Phillips, Caltech Emmanual Caux, CESR Jürgen Stutzki, Univ. Köln Science Drivers: Visit the HIFI Science Page at SRON.   Instrument Control Center:  HIFI-ICC - operational nerve center and Project Office site at the PI institute in Groningen, NL Properties and Expected Sensitivities: Mixer Band1 Element 1 SIS3 2 SIS4 3 SIS4 4 SIS4 5  SIS5 6L,6H2 HEB6 Frequency Coverage [GHz] 480-640 640-800 800-960 960-1120 1120-1250 1410-1910 Beam Sizes (Half Power Beam Width, averaged) [arcsec] 41 29 25 21 18.5 14.5, 12.5 Receiver Noise (DSB7, Baseline/Goal) [K] 90/84 130/120 170/160 210/190 370/210 650/650 Flux Limit (5-sig, 1hr, R=104) [Jy/mK] 1.5/3.4 2.0/4.4 2.3/5.1 2.5/5.6 2.7/6.0 4.6/10 Line Flux Limit (5-sig, 1hr, R=104) [10-18 W m-2] 0.9 1.4 2.0 2.6 3.2 7.0 Line Scan (1-sig, 24hr, f=1MHz) [mK] 16 16 16 16 16 34 1 Two mixers per band provide dual (H and V) polarization. 2 Band 6 is divided into Low (1410-1703 GHz) and High (1703-1910 GHz) regimes, each employing separate mixer assemblies and local oscillator chains. 3 Nb-Al2O3-Nb 4 NbTiN-Al2O3-Nb 5 NbTiN-AlN-NbTi 6 NbN phonon cooled 7 Dual Side Band convolved. Spectrometers and Resolutions: Wide Band Spectrometer Acousto-Optical Spectrometer 4 x 4 GHz sections 1 MHz (0.6 km s-1 @ 480 GHz) High Resolution Spectrometer Digital Auto-Correlator 2, 4 or 8 x 250 MHz sections (max 2 GHz bandwidth) - 550 MHz samplers 0.14, 0.28, 0.56, 1.0 (wide band mode) MHz   Radiometric Calibration Uncertainty:  10% baseline, 3% goal. Hardware Fabrication: 22 institutes in 11 countries   NASA-funded hardware:   NASA is providing the mixers and local oscillator chains for the two highest bands, 5 and 6 (where 6 is actually divided into two phonon-cooled HEB bands), as well as other local oscillator components for bands 1 through 4, and power amplifiers. Work has been conducted at JPL. Observing Modes:  Single Target, On-the-Fly Mapping, and Spectral Scan Astronomical Observing Templates (AOTs), calibrated in modes employing position switching, dual beam switching, frequency throwing, and thermal load chopping. An observer's manual will be made available by the Herschel Science Center (HSC); important information on the observing mode defintions, applications, and restrictions is found in the HIFI Observing Modes Description Document, written for HIFI team members and users. Observation Planning and Proposal Submission Tools:  available in Herschel-SPOT (HSPOT), adapted from the Spitzer Planning and Observation Tool by arrangement between the NHSC, the Spitzer Science Center, and the HSC. Data Access and Processing:  The Herschel data archive will be hosted at ESA's European Space Astronomy Centre (formerly Vilspa) in Villafranca del Castillo, Spain.  Users of the ISO, XMM, and IUE archives will be familiar with this location.  Unlike the ISO data processing piplines, however, which were based variously on fortran, IDL, and C, the Herschel Standard Product Generation software is being implemented in java, based on development in the interactive Data Processing (DP) environment of the exportable Herschel Common Software System (HCSS).  Data processing in the HCSS is also rooted in the object-oriented java language,  with Jython scripting cabilities in the user interface.  The HIFI interactive DP environment is part of the HCSS, and is being used during pre-launch instrument tests and then during operations by calibration scientists.   The HCSS and its instrument DP environments will be available to users. A web-based resource dedicated to HIFI Data Processing is being developed by the NHSC and can be found here. Back to the top

HIFI Support at the NHSC

Our Tasks  The NHSC has a growing group of scientists and developers dedicated to supporting US astronomers who anticipate making use of HIFI in guaranteed and open time science programs.  However, we are not (or not only) an observer support group for information relay.  Effecitve support comes from participating in the pre-launch preparations, check-out, and routine maintenance activities in calibration scientist and software developer roles, in agreement with and coordination by the HIFI ICC "primary node".  This includes as many phases as our staff can manage with time and travel, particpating in uplink development (observing modes, observation planning software), basic data processing, scientific analysis software development, instrument testing and performance verification.   Since our scientists also anticipate using HIFI in Guaranteed and Open Time Key Programs, they can be relied upon to provide the highest quality support in program preparation, observation planning, and data access, processing and management, with specific attention to needs of the US astronomical community. In addition to NHSC's helpdesk system, these pages will provide HIFI-related information about observation planning and data processing workshops, a frequenly asked questions page, a wiki-based web collaboration between HIFI users (according to need and interest), and pathways to additional documentation and scientific resources.  These will appear in time leading up to the Announcement of Opportunity for Open Time Key Programs. Who We Are Steve Lord  - Liaison Scientist Pat Morris - Liaison Scientist, group lead Joan Xie - Software Engineer 30+ years combined experience with the building, testing, operation, and calibration of instruments built and shot into space on observatories for doing science, including ESA's Infrared Space Observatory and NASA's Spitzer Space Telescope. We also receive valuable assistance and guidance in system architecture and infrastructure from John Rector and Jonathan Kakumasu. Back to the top