EMBRACE Pathfinder for SKA EMBRACE Steve Torchinsky 1 - - PowerPoint PPT Presentation

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EMBRACE Pathfinder for SKA EMBRACE Steve Torchinsky 1 - - PowerPoint PPT Presentation

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EMBRACE Pathfinder for SKA EMBRACE Steve Torchinsky 1 SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 Dense Aperture Plane Array Fully sampled, unblocked aperture Large field of view (~100 sq. deg) `

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1 SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014

EMBRACE Pathfinder for SKA

EMBRACE Steve Torchinsky

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 2

Dense Aperture Plane Array

`

  • Fully sampled,

unblocked aperture

  • Large field of view

(~100 sq. deg)

  • Extremely fast survey

machine for HI at cosmological redshifts

  • Ideal for BAO survey
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Electronic MultiBeam Radio Astronomy ConcEpt

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4 SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014

Commissioning Team at Nançay

  • Steve Torchinsky (Nançay)
  • Benjamin Censier (Nançay)
  • Henrik Olofsson (Onsala)
  • Aris Karastergiou (Oxford)
  • Maciej Serylak (Oxford)
  • Patrice Renaud (Nançay)
  • Christophe Taffoureau (Nançay)

The Boys of Summer

Control/command system

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 5

Electronic MultBeam Radio Astronomy ConcEpt

 EMBRACE is an AAmid Pathfinder for SKA

 Largely funded within EC FP6 Project SKADS (2005-09)  For EMBRACE:  ASTRON: Project Leader, overall architecture, antennas,

industrialization,...

 Nançay: Beamformer Chip, Monitoring and Control Software  MPI Bonn and INAF Medicina: design of multiplexing circuits for

RF reception, down conversion, command/control, power supply

 Two demonstrators built. One at Westerbork (132 tiles) and one at

Nançay (64 tiles)

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 6

Two EMBRACE sites

EMBRACE@Nançay EMBRACE@Westerbork

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 7

EMBRACE signal chain

 Nançay: 4608 Vivaldi antenna elements  Westerbork: 9504 Vivaldi antenna elements  Single polarization (second polarization antennas are in place, but only one

polarization has a complete signal chain)

 4 level hierarchical analog beamforming/signal summing

Beamformer chip:

−

4 inputs, 2 outputs (2 independent beams)

−

45º phase steps

Analog summing output from 3 beamformer chips

Analog summing of 6 inputs = 1 tile (72 elements)

15m cable → Analog summing of 4 inputs = 1 tileset

Down conversion

  • Nançay: 32 inputs to LOFAR backend

(16 A-beam, and 16 B-beam)

  • Westerbork: 165 inputs to LOFAR backend

(132 A-beam, and 33 B-beam)

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 8

EMBRACE characteristics

 500 – 1500 MHz

– But high pass filter at 900 MHz to avoid digital television

 Nançay: 70 m2 (8.5m X 8.5m)  Westerbork: 148 m2 (12.7m X 11.6m)  Instantaneous RF band: 100 MHz  Maximum instantaneous beam formed:

– Can trade off band width vs. number of beams – Nançay

  • 36 MHz x 2 directions (single polarization)
  • 186 “beamlets” each of 195.3 kHz bandwidth
  • i.e. 3 “lanes” for high speed data from RSP

– Westerbork

  • 48 MHz x 2 directions (single polarization)
  • 248 “beamlets” each of 195.3 kHz bandwidth
  • i.e. 4 “lanes” for high speed data from RSP
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Hierarchical Beamforming

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4 elements phased Together in the Beamformer microchip

Hierarchical Beamforming

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11 SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014

Beamformer Chip

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4 elements phased Together in the Beamformer microchip

Hierarchical Beamforming

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3 beamchips on a Hexboard (12 elements)

Hierarchical Beamforming

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6 hexboards in a tile (72 elements)

Hierarchical Beamforming

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Two coaxial outputs per tile

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6 hexboards in a tile (72 elements)

Hierarchical Beamforming

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4 tiles in a tileset (288 elements)

Hierarchical Beamforming

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 18

4th stage analog beam forming @Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 19

Control and Down Conversion

  • Last stage analog summing of four tiles
  • 2-stage mixing to convert RF down to

150 MHz +/- 50MHz

  • Ethernet protocol for beamformer chip

parameters and housekeeping

  • 48V DC
  • RF + Digital Commands + Power

all on the same coax!

CDC cards designed by MPIfR/INAF-IRA/ASTRON

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 20

LO distribution

  • Local Oscillator

distributed to all CDC cards via cascaded power-splitters

  • Correlated mixing

products between tilesets could explain correlator offset

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 21

LOFAR Backend

  • Output from CDC

goes to LOFAR Receiver Unit (RCU) boards for digitization

  • And then to LOFAR

Remote Station Processing (RSP) boards for digital beamforming

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 22

Pulsar acquisition system provided by

  • U. Oxford.

Aris Karastergiou

High Speed Data Acquisition

LOFAR Remote Station Processing Boards for digital beamforming

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 23

System Control and Data

  • Enormous flexibility with the dense array

– Multi-beam – Instantaneous reconfiguration – Real time calibration – Multiple observing mode possibilities with tradeoff between bandwidth, number of beams, field of view

MAC developed at Nançay provides a friendly Python interface for the user to setup complicated

  • bserving runs
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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 24

Some results

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 25

Pulsar B0329+54

Pulsar B0329+54 1175.6MHz 6 November 2012 >9 hours tracking EMBRACE@Nançay connected to ARTEMIS backend (courtesy U. Oxford)

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 26

Drift Scan of Cas-A

  • Gaussian main lobe
  • FWHM 1.476º
  • 1.2λ/D = 1.486º

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 27

Drift scan of the Sun

90 dB 110 dB 4000 secs 1420.4MHz EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 28

Imaging using X-let statistics

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 29

Multibeaming

80 dB 100 dB 7000 secs 1420.4MHz EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 30

ON-OFF pointing strategy

  • On and Off observations can

be done simultaneously with EMBRACE (multibeams)

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 31

Another fix: Flat Fielding

Cygnus A Same data! (before/after fix)

GPS satellite (strong source) No change

Stable background “image” due to correlator offset

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 32

Correlator Offset

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 33

Galaxy Detection: M33

Image by deepskycolors.com

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 34

Galaxy Detection: M33

OFF timeline shifted to align with ON (i.e. same Az-El pointing, earlier time) (ON – OFF)/OFF Baseline fit and interpolate past RFI channels Spectrum of M33

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 35

Galaxy Detection

Only 999 999 999 to go ...

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 36

Pulsar monitoring

  • Programme of

(nearly) daily monitoring of pulsar B0329+54 at 970MHz and 1176MHz simultaneously

  • Possibility to detect

accretion events in the long term (see e.g. Brook et al. ArXiv:1311.3541v1)

EMBRACE@Nançay

82 observations at 970MHz to date

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 37

B0329+54 at 970MHz

  • 82 pulse profile measurements

between 18 Nov 2013 and 1 June 2014

  • Tests stability and reliability of the

system

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 38

B0329+54 at 970MHz

  • 82 pulse profile measurements

between 18 Nov 2013 and 1 June 2014

  • Tests stability and reliability of the

system

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 39

Dispersion Measure

  • Dispersion by the

plasma between

  • bserver and source

(Interstellar Medium)

  • DM is a measure of

the plasma column density

  • DM is indirectly a

measure of distance

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 40

DM Seasonal Variation

  • Seasonal variation of DM

measures difference in column density along line of sight from different points in Earth's orbit

EMBRACE@Nançay

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 41

EMBRACE Future Work

  • astro observations

– daily pulsar B0329+54 at two frequencies: 970MHz 1176MHz

  • possible detection of an accretion event on B0329
  • a good demonstration of long term stability and reliability

– repeat M33: spectroscopic detection of a galaxy – mapping M31 with multibeams (M31 is the Andromeda Galaxy) – M42 Radio Recombination Lines (M42 is the Orion Nebula)

  • High spectroscopic resolution observation

– Intensity mapping together with PAON-4

  • technical tests/improvements

– implement improved calibration for tilesets

  • i.e. better similarity of pointing and main lobe profile between tilesets

– use full bandwidth: i.e. 186 beamlets

  • up to now, almost all our tests are with only 61 beamlets

– 3-lane data acquisition from the RSPs – acquisition on UNIBOARD with integrated real-time RFI flagging – simultaneous data acquisition of the same beam on different acquisition systems

(ARTEMIS and UNIBOARD)

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SKA-EMBRACE, Steve Torchinsky, 21cm Paris Intensity Mapping Workshop, 4 June 2014 42

EMBRACE and PAON-4