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

Science at Q-band Manchester 14-15 September 2009Science at Q-band Manchester 14-15 September 2009

1)1) Design studies & sub-system prototypingDesign studies & sub-system prototyping for for future future large-format Q-band FPA “cameras” on large large-format Q-band FPA “cameras” on large telescopestelescopes

2) MIC + MMIC devices from within Europe. 2) MIC + MMIC devices from within Europe.

APRICOTAPRICOT AAll ll PPurpose urpose RRadio adio IImaging maging CCameras ameras OOn n TTelescopeselescopes

Peter WilkinsonPeter WilkinsonU. ManchesterU. Manchester


EC Framework7 “RadioNet” EC Framework7 “RadioNet” Instrumention R&DInstrumention 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)


Yebes-40mYebes-40m

Effelsberg-100m(new active 2ry

mirror)

Some European Q-band telescopes Some European Q-band telescopes

SRT 64-m


Science StrategyScience Strategy• ““Cameras” enable these telescopes to make Cameras” enable these telescopes to make

new surveys in scientifically rich range 33-new surveys in scientifically rich range 33-50 GHz – 50 GHz –

• Continuum and spectroscopy: observations Continuum and spectroscopy: observations inin different weather conditionsdifferent 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 Follow-up with EVLA, VLBI, VSOP-2, ALMA Band 11

• Complement other mmComplement other mmsub-mm observationssub-mm observations

• Complement CMBR observations e.g. PlanckComplement CMBR observations e.g. Planck


APRICOT: BasicsAPRICOT: Basics

• Operating range: 33-50 GHz • spectrally rich + many continuum applications

• All Stokes parameters + spectroscopy at same time• Continuum band split into (n x few GHz) sub-Continuum band split into (n x few GHz) sub-bands forbands for atmospheric & spectral discrimination. atmospheric & spectral discrimination.

• Broad-band IF output selected from anywhere Broad-band IF output selected from anywhere within within overall band, sent to high-speed digital FTS overall band, sent to high-speed digital FTS ((UNIBOARD)UNIBOARD)


Molecular Line SpectroscopyMolecular Line Spectroscopy

• Star-forming regions & circumstellar envelopesStar-forming regions & circumstellar envelopes

• Imaging plus modelling Imaging plus modelling temperature & density temperature & density

• Many carbon-chain species in the 30-50 GHz band (HCMany carbon-chain species in the 30-50 GHz band (HCnnN n=3,5,7; N n=3,5,7; CCnnH n=5,6; CH n=5,6; CnnS n=1,3,5) diagnostic of cold dense quiescent gasS 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) • CHCH33CN (hot core species); SO (Zeeman sensitive)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 galaxiesDistances & mass estimates of dusty galaxies


• 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 StudiesContinuum 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

Science at Q-band Manchester 14-15 September 2009Science at Q-band Manchester 14-15 September 2009MAS Meeting Pasadena, 27 April 2005

Scientific Synergy Scientific Synergy

for progress in cosmology mustunderstand the unpolarizedand polarized foregroundswith exquisite precision

a wealth of astrophysics becomes accessible if we studyboth galactic and extragalactic foregrounds with precision

Surveys with radio cameraslink these fields


Relevant FPA experienceRelevant FPA experience


EMBA: 32 GHz (MPIfR) EMBA: 32 GHz (MPIfR)

7-beam horn array 7-beam horn array with different with different propertiesproperties

Dewar interiorDewar interior


• 7 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 18-26 GHz (IRA)


OCRA 26-36 GHz OCRA 26-36 GHz (U. MAN)(U. MAN)

26-36 GHz 16-beamsContinuum (UMAN)

• Single polarisation continuum 26-36 GHz

• Direct detection

• All-MMIC receiver based on WMAP/Planck- LFI design

• NGST InP MMICs

• Horns all cold – behind self-supporting 480mm vacuum window


• 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......


Hence the need for major Hence the need for major changes in approach…changes in approach…


Architectures for highly integrated multi-pixel Architectures for highly integrated multi-pixel receiversreceivers

• 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 ArchitectureWP1 Receiver Architecture

Deliverables are mainly design study reports

MPIfR; IRA, UMAN, CAY, TCfA


• 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


• To develop and secure European supply of world-standard MMIC devices for astronomy

• To seek improved noise performance:• TLNA 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 developmentUMAN; IRA; MPIfR; CAY; URomeTV


• 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+


WP4: Device TestingWP4: 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


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)


WP5: Data handlingWP5: 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


Emerging Specification

Npixels and configuration

25100 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 Tsys (>5 K) could be tolerated for larger Npix

Total RF Bandwidth

33-50 GHz Waveguide band: Goal is 17 GHz BW to backend Which few GHz is least important?

Polarisation type LCP/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


Advice requestedAdvice 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)

Documents

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