2 nd SKADS Workshop: Introduction “What is it about?”

Peter WilkinsonSKADS Workshop: Paris10 October 2007

22ndnd SKADS Workshop: SKADS Workshop: Introduction “What is it Introduction “What is it

about?”about?”

Peter Wilkinson

University of Manchester


The Square Kilometre The Square Kilometre ArrayArray

The world’s most exciting astronomy project for the next 20 years…

whose “DNA” is European !


First First things…..Hydrogenthings…..Hydrogen

Provides a different view of the universe.. ..radio astronomy provides the tools to study it

HI is principal driver

for the size of the

SKA and its

“focus” frequencies


Square Kilometre Square Kilometre ArrayArray

But current radio telescopes, based on pre-1980s But current radio telescopes, based on pre-1980s technology, technology,

are not adequate…are not adequate…

Science now demands:Science now demands:1. Large increase in sensitivity 1. Large increase in sensitivity 1km 1km2 2 (~50 x)(~50 x)– Observe neutral hydrogen throughout the universeObserve neutral hydrogen throughout the universe

2.2. Large increase in field-of-view Large increase in field-of-view >30deg >30deg2 2 (>200x)(>200x)– Survey entire skySurvey entire sky

3.3. While maintaining a broad frequency rangeWhile maintaining a broad frequency range -- Maximise science potentialMaximise science potentialDiscovery Potential = Area X f.o.v. ~ 10000 x betterDiscovery Potential = Area X f.o.v. ~ 10000 x better


Square Kilometre ArraySquare Kilometre Array

Many new possibilities for radio astronomyMany new possibilities for radio astronomy– Multipixel sensors with wide bandwidths Multipixel sensors with wide bandwidths – Far higher data rates and processing power Far higher data rates and processing power – New methodologies in software engineering New methodologies in software engineering – Grid technologyGrid technology– New materialsNew materials

• We have the technology to build SKAWe have the technology to build SKA• The challenge is to build it at an affordable costThe challenge is to build it at an affordable cost

– In close synergy with industryIn close synergy with industry


Antenna + Single Pixel Feed

Antenna + Phased Array/ (Cluster) Feed

Aperture ArrayHPC

0.3 - 1GHz

~ few GHz

SKADS


“Pathfinder” development (~1% SKA)• ATA (US): Small Dish + Single Pixel Feed [High ]• LOFAR (NL): Dipole Array [Low ]• MWA/LWA (US) Aperture Array [Low ]• ASKAP (Aus/Ca): Dish + Phased Array Feed [Mid ]• MeerKAT (SA): Dish + Single Pixel/Cluster Feed [Mid

High ]

Design Studies• EU SKADS: Aperture Arrays [Low-mid transition ]• US TDP: Dish/Smart Feed [Mid-high transition ]

SKA international SKA international


Science Pathfinder ActivityScience Pathfinder Activity

ATA

KAT

ASKAP

MWA

LOFAR

meerKAT

USA: TDP


EC FP7: PrepSKAEC FP7: PrepSKA

“PrepSKA” programm covers period 2008-2011

- Central Design and Integration Team (CDIT) coordinating international R&D needs new national funding for continuation of SKADS R&D after 2009

- Costed System Design - Further site studies - Governance, Legal Framework, Procurement, Funding Model


Some outcomes from Some outcomes from SKA2007SKA2007

• Basic SKA specifications agreed!

• The SKA will be a continuously evolving telescope

• The dish specifications will be formulated in mechanical terms, with a view to extending the high frequency limit of “SKA-mid” to 10 GHz

• Aperture Arrays form part of all current design options up to 500 MHz

• The large survey speed required for the all-sky HI survey for baryonic oscillations is linked to the maturity of AA technology


A phased A phased implementation…implementation…

• Costed design 2008-2011 (within PrepSKA)

• Production readiness phase 2012

• Start of construction 2013

• Initial focus on SKA-mid frequencies

• First 10% (Phase 1) complete 2015-2016 – stand alone science case

• Target completion date of SKA mid+low 2020

• Target construction cost (SKA mid + low): 1500 M€ operating costs: ~100 M€/yr


Aperture ArraysAperture Arrays SKADS SKADS

• 1980s: Manchester and ASTRON ideas for large collecting area for HI

• 1990s: ASTRON Phased array R&D programme (van Ardenne)• 2002: Thousand Element Array THEA

• 2003: European R&D planning begins - based on large-scale “Aperture Arrays”• 2004: EC FP6 Design Study Programme SKADS proposed• 2005: SKADS funding starts in July


SKADSSKADS

• FP6 SKADS designed as a “complete” programme– Scientific and technical simulations

– Basic technology R&D

– Practical demonstrators of AAs & electronic beam forming

– A costed design for an entire SKA

• Programme unusual for EC: national >> EC funding – EC funding was the crucial catalyst

• Now reached the half-way point – assessment time…– This 2-day meeting

– The mid-term review by the EC on Friday


Upcoming European Upcoming European IssuesIssues

• “SKADS in context of PrepSKA” – need to secure funding– overall system design; cost modelling; manufacturability;

industry links

• A big issue: the “minimum capability demonstrator for AAs”

• Need to prove AA capability in many areas

– Achievable system temperature – vital to get below 50K

– Calibratability sidelobes dynamic range

– Environmental robustness on an SKA site

• Effect of ambient temperature variations

• Effect of sunlight, dust and water ingress, lighting strike

• Want a large (5000m2) AA component in early phase SKA


Now let’ s get down to the details…


The Hydrogen Array: 1990The Hydrogen Array: 1990 Radio Interferometry: Theory, Techniques and Applications I AU Coll. 131, ASP Conference Series, Vol. 19, 1991 T.J. Cornwell and R.A. Perley (eds.)

THE HYDROGEN ARRAY

P. N. WILKINSON University of Manchester, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire SK11 9DL, United Kingdom

ABSTRACT The time is ripe for planning an array with a collecting area of 1 km2 (14 times larger than Arecibo and 75 times larger than the VLA). In view of its major astronomical target I have dubbed this concept 'The Hydrogen Array', although 1µJy continuum sources will also be reliably detected. I present some initial thoughts about the issues involved.


ReviewHi-freq SKA

Design

Production Readiness

ReviewSKA-mid+low

06 | 08 | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 |

Concept Des’nConcept Des’n System DesignSystem Design Prod’n Readiness & Prod’n Readiness & System Verif’nSystem Verif’n

SKA mid +low Construction & SKA mid +low Construction & CommissioningCommissioning

SKA-hi ConstructionSKA-hi Construction

Sites short-listed

EC-FP7: PrepSKASystem design Funding Governance Site Seln

Initial SKA specs

External Engineering Review of design

Reference Design selected

Pathfinder Suite Construction

Early ScienceEarly Science SKA mid+low SKA mid+low

SKA-mid+lowSKA-mid+lowCompleteComplete

SiteSelect

SKA SKA PathfinderPathfinder

ssCompleteComplete

SKA timelineSKA timeline

Concept design for SKA-hiConcept design for SKA-hiSystem design System design

SKA-hiSKA-hi

Costed SKA low+mid designs complete

Pathfinder science

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2 nd SKADS Workshop: Introduction “What is it about?”

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