Phased Array Feeds for Parkes Robert Braun Science with Parkes @ 50 Years Young
Outline PAFs in the SKA context PAFSKA activities Apertif, BYU, NRAO, NAIC, DRAO, ASKAP ASKAP PAF MkI ASKAP PAF MkII Parkes: a PAF prototype/science test-bed
PAFs in the SKA context SKA Dish array specifications: 0.45 ~10 GHz (Phase1) ~25 GHz (Phase2) Need to define feed/receiver modules, reserve focus real estate that insures 50+ year upgrade lifetime, eg. 0.45 1.1 GHz ~ 1.5x1.5 m B1 1 2.5 GHz ~ 1x1 m B2 2.3 5.8 GHz ~ 0.5x0.5 m B3 5.5 14 GHz ~ 0.25x0.25 m B4 12 25 GHz ~ 0.13x0.13 m B5 Need to be PAF-ready when cost effective
Getting more from each antenna Reflector Collects
Getting more from each antenna Reflector Collects Phased Array Feed collects more (~every λ/2)
Getting more from each antenna Reflector Collects Phased Array Feed collects more (~every λ/2) allows corrections
PAFSKA Activities: IEEE-TAP Special Issue - June 2011 phased array feeds 8 papers
PAFSKA Activities: Apertif ( ( Prototype Vivaldi PAF installed at WSRT Van Cappellen et al. 2011, URSI GASS2011 *+!),-.(- 783 783 /01,2#0&,$% *+*6!/$06 "#$%&'(%) 5 " )0&0!%(&<$#= ;$##(10&$# >&$#0?( @ ABB1,%(! C#$/(--,%? 9(/(,:(# 3 4 3 4 3 4 7$/01!;$%&#$1!D%,& 5 " 4,-.!1(:(1! C#$/(--,%? /$%&#$1!%(&<$#= "#(FG(%/H!0%)!&,I(! -&0%)0#) ;$%&#$1!@!D-(#!E%&(#B0/( (((((( ( "#$%&'!()!*+,-./"!01234!5#6$&67!81'9:;!6<5!6!=&2:2:>='!+*"!#<?:611'5!#<!:@'!AB-.!8&#$@:;)!,
PAFSKA Activities: Apertif Prototype Vivaldi PAF installed at WSRT Van Cappellen et al. 2011, URSI GASS2011!!!!!!!"#$%&'()'*&+,$%&-'%+-"+."/0'1+..&%0,'/0'.2&',34'/5'6('78!'&9&:&0.,';2&%&'&+<2'1+0&9':&+,$%&,'6=6'-&#%&&,' >9&5.?'+0-'.2&':&+,$%&-',&0,"."@".4'/@&%'.2&'5"&9-'/5'@"&;'+.'AB(C'*DE'>%"#2.?)'!
PAFSKA Activities: Apertif Prototype Vivaldi PAF installed at WSRT Van Cappellen et al. 2011, URSI GASS2011 High efficiency illumination, η B ~ 0.75, cf. horn η B ~ 0.55!!!!!!!!!!!!!!!!!"#$%&'()'!%*+,'-"&.'*/',0&'%&/1&2,*%'31&/,45'67#+",$8&'*/',0&'%&/1&2,*%'"11$6"+7,"*+'*/'7'0*%+'/&&8'32&+,%&4'' 7+8'9:!'3%"#0,4)'!!!!!!!!!!!!!!!!!!!!
PAFSKA Activities: Apertif Prototype Vivaldi PAF installed at WSRT Van Cappellen et al. 2011, URSI GASS2011 Current performance: T sys /η ~ 89 K, final < 73 K!"#$%&';)'<&7=$%&8':&>?=@='*/'7+'*+A7B"='9:!'C&76)'
PAFSKA Activities: Apertif Prototype Vivaldi PAF installed at WSRT Van Cappellen et al. 2011, URSI GASS2011 Standing wave reduced by > 20 db with PAF $ $ $!"#$%&'()'*&+,$%&-',&.,"/"0"/1'0&%,$,'2%&3$&.41'52'+'65%.72&-'-",6'89&2/:'+.-'+',".#9&';<!'&9&=&./'8%"#6/:)'' <99'9".&,'+%&'.5%=+9">&-'/5'$."/1'=&+.)' #
PAFSKA Activities: Cortes/NAIC/BYU National Astronomy and Ionosphere Center ;<7F;G'G".,H8HIH*/'9*J@/' 9J#5"/'9K""@L'M&*"#';<'F;G' N')O'8".$,' P".$'9)IH@';&AI"' P.&@QH@*R' L-Band N b! b BW A eff T SYS A EFF / T SYS [deg 2 ] [MHz] [m 2 ] [K] [m 2 /K] SVS/ AO SVS AO 1 0.0028 3'8".$'9:9 300 32750 ;< '='2631>32 27? '@"A 1213 1 '$ B 'C 71 '-DE' 1 ALFA 7 0.0028 300 32750 27 1213 7 AO FPA 40 0.0028 300 32750 35 936 23.8!"#$%&'()#*+,'-''-./0'1233' 4"56'7'
PAFSKA Activities: Cortes/NAIC/BYU 8*'*9"':;.<)#$' National Astronomy and Ionosphere Center!"#$%&'()#*+,'-''-./0'1233' 4"56'7'
PAFSKA Activities: Cortes/NAIC/BYU National Astronomy and Ionosphere Center (#/)8"&9:,';".,9<9=9*/'>*?@/' ()&:"A*'B' C.A*)&'D9&@)E' B4';9=*"#F;).$' G"H)&'' I)&"/:)$<'@)$",' J9A)=",'12C'!#)?&@'K=.&"'L2C' ;9#,*'>*.8"'M2C'!"#$%&'()#*+,'-''-./0'1233' 4"56'7'
ASKAP PAFs 36 12 m dishes 30 deg 2 FOV 50 K T sys 700 1800 MHz 300 MHz IF BW 2 Tb/s/antenna Digital beamforming Online imaging
Connected Chequerboard Array Advantages Low receiver noise high matching/radiation efficiencies High bandwidth 2.6:1 Easy/robust manufacture weather shielded temp. stabilised to 25 C could be cryo-cooled
ASKAP MkI PAF
ASKAP Mk I PAF
Connected Chequerboard Array Overview Dense array matched to low-noise amplifiers (LNAs) Inherently broadband Self complementary Z 377 Ω Complete sampling of focal region fields Digital beamformer LNA + Conversion + Filtering Weighted (complex) sum of inputs Hay, S.G. and O Sullivan, J.D., Radio Science, 43, RS6S04, 2008. Hay, S.G., O Sullivan, J.D. and Mittra, R., IEEE TAP, 59, 3, 2011.
Parkes
ASKAP PAF MkI (Early Measurements) Aperture-Plane Array T rec for Boresight Beam Sensitivity matching conditions: Hay, IJMOT 5,6,2010 & ICEAA 2010. Measurement: unpublished
ASKAP PAF MkI (Early Measurements) Focal-Plane Array T sys /η for Boresight Beam T sys /η (K) Beamformed System Temperature on Efficiency ASKAP MkI Prototype PAF - MaxSNR Boresight Beam parkes_20110921\f_1934-638 180 160 140 120 100 80 60 40 20 0 1.25 1.3 1.35 1.4 1.45 1.5 Frequency (GHz) Assuming η = 0.8, implies T spill ~ 10 K MkI already achieving T sys = 50 60 K, for 0.7 1.2 GHz XX YY
ASKAP PAF MkII Key enhancement areas: RF over fibre Electronics packaging Mechanical packaging Cooling Control/monitoring Power supply Checkerboard performance The enhancements aim to: Reduce cost, weight, complexity and construction time by 50% Decrease maintenance time easier access/servicing Increase in performance of PAF
ASKAP PAF MkII (cont.) Software Defined Radio Frequency down conversion no longer required Direct sampling of three RF bands in excess of 300MHz BW ADC clock is only system clock central site distribution Next generation Kintex-7 FPGAs Lower cost and power per unit processed Faster IO (10Gbps data commsand 800MTps DDR3 memory) Next generation Multimode parallel optics Enables backplane less design (optical cross connect) Lowers data transport cost between beamformerand correlator Simpler data communications firmware System packaging Low cost PC COTS components case, power, cooling, etc.
ASKAP PAF Modelling Aperture-Plane Array T rec for Boresight Beam source: Hay 2011, unpublished
ASKAP PAFs Next Steps 2011 PAF on dish at Parkes PAF on dish at MRO 2012 6 Mk I PAFs operating on antennas at MRO ASKAP Design Enhancements Good T sys over full band Reduce complexity/cost/power/weight order 50% RF over fibre, direct sampling & Virtex 7 Build 6 Mk II PAFs 2013 Full rollout of electronics Early commissioning science Continue with Mk II deployment on all 36 dishes
Parkes: PAF prototype/science test-bed Develop standardised SKA-compliant PAF interface/ footprint together with SPO Deploy standardised interface/footprint version of ASKAP MkII system ~30 Beams: 700 1800 MHz, T sys < 55 K, high η B RFoF is vital for Parkes installation, hence no Mk I Deploy MkIII, IV PAF systems as developed for SKA Designed for SKA B1, B2: 0.45 1.1 and 1 2.5 GHz Possibly implement cryo for maximum performance Explore higher SKA frequency bands: B3, 4 and 5 Enable wide-fov science on Parkes with PAF prototypes as available
CSIRO Astronomy & Space Science Robert Braun Chief Scientist Phone: +61 2 9372 4271 Email: Robert.Braun@csiro.au Web: www.atnf.csiro.au www.csiro.au/org/cass.html Thank you Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au