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Science at Q-band Manchester 14-15 September 2009 1)Design studies & sub-system prototyping for future large-format Q-band FPA “cameras” on large telescopes.

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Presentation on theme: "Science at Q-band Manchester 14-15 September 2009 1)Design studies & sub-system prototyping for future large-format Q-band FPA “cameras” on large telescopes."— Presentation transcript:

1 Science at Q-band Manchester September )Design studies & sub-system prototyping for future large-format Q-band FPA “cameras” on large telescopes 2) MIC + MMIC devices from within Europe. APRICOT All Purpose Radio Imaging Cameras On Telescopes Peter Wilkinson U. Manchester

2 Science at Q-band Manchester September 2009 EC Framework7 “RadioNet” Instrumention R&D APRICOT : Q-band camera subsystems + European MIC/MMICs (Caltech/JPL MMIC array spectrographs & NRAO FPA goals overlap with APRICOT) AMSTAR+ : mm/sub-mm cameras subsytems (SIS, MMIC) (W-band FPAs overlaps with APRICOT) (UNIBOARD: multi-purpose digital backends)

3 Science at Q-band Manchester September 2009 Yebes-40m Effelsberg-100m (new active 2 ry mirror) Some European Q-band telescopes SRT 64-m

4 Science at Q-band Manchester September 2009 Science Strategy “Cameras” enable these telescopes to make new surveys in scientifically rich range GHz – “Cameras” enable these telescopes to make new surveys in scientifically rich range GHz – Continuum and spectroscopy: observations in Continuum and spectroscopy: observations in different weather conditions different weather conditions In “intermediate” gap between SKA and ALMA In “intermediate” gap between SKA and ALMA Follow-up with EVLA, VLBI, VSOP-2, ALMA Band 1 Follow-up with EVLA, VLBI, VSOP-2, ALMA Band 1 Complement other mm  sub-mm observations Complement other mm  sub-mm observations Complement CMBR observations e.g. Planck Complement CMBR observations e.g. Planck

5 Science at Q-band Manchester September 2009 APRICOT: Basics Operating range: GHz spectrally rich + many continuum applications All Stokes parameters + spectroscopy at same time Continuum band split into (n x few GHz) sub-bands for Continuum band split into (n x few GHz) sub-bands for atmospheric & spectral discrimination. atmospheric & spectral discrimination. Broad-band IF output selected from anywhere within Broad-band IF output selected from anywhere within overall band, sent to high-speed digital FTS ( UNIBOARD) overall band, sent to high-speed digital FTS ( UNIBOARD)

6 Science at Q-band Manchester September 2009 Molecular Line Spectroscopy Star-forming regions & circumstellar envelopesStar-forming regions & circumstellar envelopes Imaging plus modelling  temperature & densityImaging plus modelling  temperature & density Many carbon-chain species in the GHz band (HC n N n=3,5,7; C n H n=5,6; C n S n=1,3,5) diagnostic of cold dense quiescent gasMany carbon-chain species in the GHz band (HC n N n=3,5,7; C n H n=5,6; C n S n=1,3,5) diagnostic of cold dense quiescent gas Other species:Other species: SiO (shock tracer); OCS (sulphur sink)SiO (shock tracer); OCS (sulphur sink) CH 3 CN (hot core species); SO (Zeeman sensitive)CH 3 CN (hot core species); SO (Zeeman sensitive) SiO masers in CSEs close to the starSiO masers in CSEs close to the star With large format cameras could survey complete clouds in one day Blind surveys in redshifted CO (1-0) Blind surveys in redshifted CO (1-0) Distances & mass estimates of dusty galaxies Distances & mass estimates of dusty galaxies

7 Science at Q-band Manchester September 2009 Surveys for Surveys for discrete sources (in polarisation) Find new types of AGN e.g. youngest CSOs follow-up with mm-VLBI & VSOP-2 imaging follow-up of GLAST transients Provide net of calibration sources for EVLA and mm-VLBI Support of Planck and all high-sensitivity CMBR experiments Continuum Studies Surveys of diffuse Galactic emission (in polarisation) Synchrotron; free-free; anomalous dust; thermal dust Need to dissect out the contributions: for ISM astrophysics and CMBR polarised foregrounds In compact regions e.g. YSOs - diagnostics of dust agglomeration in protoplanetary disks Surveys for/of clusters of galaxies via the S-Z effect

8 Science at Q-band Manchester September 2009 MAS Meeting Pasadena, 27 April 2005 Scientific Synergy for progress in cosmology must understand the unpolarized and polarized foregrounds with exquisite precision a wealth of astrophysics becomes accessible if we study both galactic and extragalactic foregrounds with precision Surveys with radio cameras link these fields

9 Science at Q-band Manchester September 2009 Relevant FPA experience

10 Science at Q-band Manchester September 2009 EMBA: 32 GHz (MPIfR)  7-beam horn array with different properties  Dewar interior

11 Science at Q-band Manchester September feed, hexagonal configuration with central feed 14 x 2 GHz IF outputs right and left polarization; Feeds and LNAs cooled at 20 K; Mechanical de-rotator to track the parallactic angle FARADAY GHz (IRA)

12 Science at Q-band Manchester September 2009 OCRA GHz (U. MAN) GHz 16-beams Continuum (UMAN) Single polarisation continuum GHz Direct detection All-MMIC receiver based on WMAP/Planck- LFI design NGST InP MMICs Horns all cold – behind self-supporting 480mm vacuum window

13 Science at Q-band Manchester September 2009 NGST MMIC performance: very good - ITAR produced great delays MMIC chips to “mass production” of LNAs  extraordinarily long Dewar: many devices, cables, wires, connectors  big, complicated Noise marker and LO distribution: simple in principle but complicated LNA power supply: complicated, huge amount of thin wires Weight: great Maintenance: maybe lots EXPERIENCE......

14 Science at Q-band Manchester September 2009 Hence the need for major changes in approach…

15 Science at Q-band Manchester September 2009 Architectures for highly integrated multi-pixel receivers Architectures for highly integrated multi-pixel receivers Modular design with well-defined interfaces Design for mechanical and cryogenic stability Optimise layout for maintenance/fault-fixing Design of monitor, control and calibration systems Integration of direct detection and heterodyne systems LO generation and distribution Design, packaging and integration of RF, IF, LO systems Establish capability to batch-produce RF, IF modules WP1 Receiver Architecture Deliverables are mainly design study reports MPIfR; IRA, UMAN, CAY, TCfA

16 Science at Q-band Manchester September 2009 Highly integrated chain with OMT, hybrids, transmission sections etc Low-loss, low size/weight, low cost, ease of manufacture Standard waveguide technology too expensive Needs technology shift  Planar technology, microstrip transmission lines and filters etc WP2: passive components Deliverables - design study reports - few pixels hardware comparing performance of conventional and “innovative” approaches ( with WP1 and WP3 ) IRA; MPIfR, UMAN

17 Science at Q-band Manchester September 2009 To develop and secure European supply of world-standard MMIC devices for astronomy To seek improved noise performance: T LNA stuck at 5-6 x Quantum Limit for >10 years: why? To explore/achieve increased levels of integration & multi-function capability within a MMIC circuit. WP3: MIC/MMIC development UMAN; IRA; MPIfR; CAY; URomeTV

18 Science at Q-band Manchester September 2009 U. Manchester 100nm InP HEMT technology innovation in materials and architecture for low-noise rapid response to new design inputs MIC/MMIC producers Fraunhofer Institute (IAF) Freiburg 100 & 50 nm GaAs mHEMT technology Multi-function MMICs Experimental 35nm processes Now interested in low-noise at cryo temps OMMIC company 70nm GaAs mHEMT technology Link with AMSTAR+

19 Science at Q-band Manchester September 2009 WP4: Device Testing Accurate measurement of noise temperature and gain fluctuation of devices at cryo temperatures not easy Results from well-respected labs often differ ! CAY have lots of experience in this arena from LNA work for Herschel (HIFI), ALMA, IRAM, ESOC etc CAY; UMAN; MPIfR, IRA; URomeTV

20 Science at Q-band Manchester September 2009 Synergy with “MMIC Array Spectrographs” Caltech/JPL: aims similar to APRICOT/AMSTAR+ Push for lowering InP pHEMT noise closer to quantum limit in collaboration with NGST Why don’t MICs and MMICs perform the same from wafer to wafer? Why don’t MMICs in modules perform as well as expected ? (QUIET experience)

21 Science at Q-band Manchester September 2009 WP5: Data handling Develop and test algorithms using the full range of multi-pixel and multi-spectral data to reduce effects of 1/f noise and atmosphere without spatial switching, (“on the fly-mapping” – strongly affects receiver concept) Develop and test figures-of-merit to support queue- scheduling of the receiver in both continuum and spectroscopic modes Combine knowledge with other mm-wave users TCfA: UMAN, IRA, MPIfR

22 Science at Q-band Manchester September 2009 Emerging Specification N pixels and configuration 25  100  Limits from optics: SRT ~30 beams for 0.5db loss  Configuration affects survey efficiency: hexagonal may not be best for beam-beam switching Tsys<50K  RX temperature <25K + sky ~ 25K.  Higher T sys (>5 K) could be tolerated for larger N pix Total RF Bandwidth GHz  Waveguide band: Goal is 17 GHz BW to backend  Which few GHz is least important? Polarisation typeLCP/RCP or X/Y  Needs detailed discussion Polarisation purity 30dB  Set by science demands  Hard to maintain 30 db over 46% BW with circular? Continuum channels per pixel 8  For atmospheric diagnosis and instant spectra.  Critical requirement for the architecture Spectroscopic coverage 17 GHz instant >2 GHz RF bands  Architecture possible to deliver all RF band, split in channels per pixel, to spectrometer with no tuning Gain stability /knee frequency ???  Acceptability? Depends on observation technique  Rapid scan rates allow on-the-fly mapping  major issue for WP5 simulations Spectroscopic channels per pixel 64k for each 2 GHz band  Demand on backend to UNIBOARD  Resolution ~30 kHz – science “would like” 15 kHz

23 Science at Q-band Manchester September 2009 Advice requested Bandwidth goal is 17 GHz (46%) split into ~8 continuum bands - which end is scientifically more important if compromises needed? Receiver is simpler if the internal switching schemes are minimised/nil – challenge is observing with 1/f gain variations and weather – experience on antenna driving requirements ? Pixel calibration: - acceptable variation between pixels? Spectroscopy - is ~2 GHz instantaneous enough? - is spectral resolution of 15 kHz = 0.1km/sec within a 2 GHz band OK? - what is the specification on bandpass ripple within channels? Polarisation specifications: - linear or circular – any comments? - separation purity: 30 dB ?- maybe hard to maintain withm circular polarisation across a 46% BW)


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