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Technologies for Radio Astronomy

Technologies for Radio Astronomy. Graeme Carrad | Assistant Director - Engineering Mark Bowen | Group Leader – Front End Technologies. CSIRO Astronomy and Space Science. JULY 2012. Outline. Technologies for Radio Astronomy CABB ATCA C/X Upgrade FAST Parkes – Future Receiver Systems.

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Technologies for Radio Astronomy

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  1. Technologies for Radio Astronomy Graeme Carrad | Assistant Director - Engineering Mark Bowen | Group Leader – Front End Technologies CSIRO Astronomy and Space Science JULY 2012

  2. Outline Technologies for Radio Astronomy • CABB • ATCA C/X Upgrade • FAST Parkes – Future Receiver Systems Technologies | Graeme Carrad| Page 2

  3. Compact Array Broadband Backend • Status • 64MHz zoom mode with all 16 zooms available has an estimated delivery date this winter season. • Late but can only apologise. • The complexity demands more experienced resources and they are not available. It is estimated at 90% complete with the remaining work being to output the data in a suitable format to cope with the data rate at 64 times the 1 MHz rate. Not all the data can come out at once. • Tim Bateman, Bob Sault and Warwick Wilson tackling, successfully, a long list of operational issues highlighted by Jamie Stevens and Robin Wark. • Last ATUC meeting it was asked, do we stop zoom development after 64 MHz delivery and fix CABB’s bugs first? – The feeling is that much will have been accomplished in bug fixes. Technologies | Graeme Carrad| Page 3

  4. ATCA C/X Upgrade Status • Australian Astronomy Ltd. funded program - upgrade funding continues until June 2013. • Prototype receiver installed on ATCA during Nov 2011. • Development of a production LNA is complete and the manufacture of LNA hardware is underway. • The manufacture of hardware and components for the production receivers is well underway. • The first two receivers (production) are currently in the CASS Marsfield laboratories undergoing modification. • Two production receivers will be installed on the ATCA during Aug – Sep 2012. Parkes receiver options| Graeme Carrad| Page 4

  5. ATCA C/X Upgrade 4.0 – 12.25GHz Feed Prototype • Existing C/X feed horn does not work above 10.8GHz. • Feed investigations carried out by CSIRO ICT Centre and BAE Systems. • Consultation with user community identified limited interest in extending operation from 10.8GHz – 12.0GHz. • A prototype 4.0 – 12.25GHz feed horn will be delivered by BAE Systems. • The feed will be tested on the ICT Centre antenna range then installed on the ATCA for evaluation. • An estimate of the cost to outfit the ATCA including new feeds and CABB signal path hardware modifications will be made.

  6. FAST Multi-beam Receiver - Feasibility Study Background • 19 beams at 1.05GHz – 1.45GHz. • CSIRO ICT Centre designing feed and OMT, CASS studying LNA and cryostat. • JBCA developing alternative designs. • Status • ICTC feed electromagnetic design complete. • CASS LNA and cryostat design underway. Parkes receiver options| Graeme Carrad| Page 6

  7. Parkes Receivers

  8. What are we considering? First stage in developing a longer term plan Wideband Receiver • 700 MHz to 4 GHz • 4 – 16GHz (18GHz?) (20GHz?)(24GHz?) PAF • Frequency coverage comparable to ASKAP PAF? 20 - 25GHz Multibeam Receiver • Does this development make the most from the feasibility studies? • Should we build another multibeam receiver? Parkes receiver options| Graeme Carrad| Page 8

  9. What would a PAF provide? • ASKAP MkII system is already achieving rather competitive Tsys/η ≈ 55 K on 12 m, likely between about 800 – 1600 MHz. • PAFs provide much better spectral baseline performance than SPFs. • New science possibilities with 36 beams: • Pulsar surveys • Deep HI for “Intensity Mapping” and “HI Cosmic Web”

  10. What do we know? Wideband Receivers • MPIfR are developing a 600 MHz - 3 GHz receiver with uncooled feed/OMT. Target of Tsys ≤ 50K • Our own investigations indicate the wideband elements are non trivial/difficult to design despite knowledge of the MPIfR program. • Cooling the feed/OMT is desirable but presents a challenge. • The wide bandwidth is likely to require a compromise - lesser performance than current receivers over some or all of the band. • This development may complement plans for future receiver rationalisation. • At this stage we do not know enough to advise on likely performance. Parkes receiver options| Graeme Carrad| | Page 10

  11. What do we know? PAF • Experience in modelling, fabricating and the performance (ASKAP). • BETA PAF exists – Mk. 1. • ADE PAF is under development but the initial results (5x4) look promising – Mk. 2. • Current BETA PAF on Parkes is likely to be an ‘experiment’. This might be a quick way to explore PAFs on a large dish but will carry an operational overhead. Additional resources required from proponents. • CASS is more likely to lead a program for a PAF with the performance of the current 5x4 (Full Bandwidth). • Modularity is necessary for future upgrades. (Cryo PAF?) • External support for a Parkes PAF has been mooted. (SIEF?) Parkes receiver options| Graeme Carrad| | Page 11

  12. What do we know? 20 – 25 GHz Multibeam Receiver • We have the experience in this frequency range. • MMIC fabrication is almost certainly required together with a significant conversion and frequency conversion scheme. • Likely high cost and longer term program to deliver. • The Parkes dish performance is poorer at these frequencies compared with the lower frequencies. • The majority of observing at Parkes (~70%) is done at lower frequencies. Parkes receiver options| Graeme Carrad| | Page 12

  13. Approaches Wideband Receivers • Conduct a feasibilty study to determine the design, performance and compromises as well as addressing some of the challenges in cooling. • This study is likely to take 6 months (best estimate). • Backend considerations aligned with Parkes needs. • Stay in touch with MPIfR progress. • A 4GHz ‘up’ proof of concept to start off would be smaller and physically less demanding, provide experience and give Parkes enhanced capability. • It may be more appropriate to start development at the higher frequency as one step in the path to the 700MHz – 4GHz receiver. • Starting with a 600MHz to 4GHz receiver addresses the majority of the observing but if the performance falls short there is knowledge gained but no suitable receiver to replace existing ones. • A successful implementation of a 700MHz – 4GHz also aligns with the strategy of reducing receiver changes. Parkes receiver options| Graeme Carrad| | Page 13

  14. Approaches PAF • Conduct a feasibility study to determine scope of work required to fit a PAF to Parkes. • How good does the PAF need to be? • Does it need to be a replacement for the centre beam of the L band multibeam? • If that can’t be achieved with current designs then that implies more development. This will set the timeline for implementation. • Can a new chequerboard and amplifiers coming from ADE developments be adapted for a BETA PAF? • Upgrade path for BETA and ADE PAF systems. • Have a design team start exploring the incorporation of BETA and ADE PAF structures into Parkes focus cabin – mechanical and heat load considerations. • Backend considerations aligned with Parkes needs. Parkes receiver options| Graeme Carrad| | Page 14

  15. Considerations Calibration • A parallel program to ensure a calibration scheme is developed along with both wideband receiver and PAF. • Single dish as opposed to array for PAF. RFI • Future developments in communications threaten low frequency band integrity. • Do we program mitigation in, or abandon specific frequency bands? • The backend complexity/cost might be defined by the need cross correlation or other mitigation techniques. Resources • There is likely to be sufficient effort available to study the feasibility of two developments in parallel i.e Wideband receivers and PAF. Parkes receiver options| Graeme Carrad| | Page 15

  16. Timelines • Nice to have studies done for the next ATUC meeting (Nov) but that seems too soon. We will report on progress of the studies then. • The June 2013 meeting might be too far away to seek advice on the outcomes of the studies so an out of session gathering might be considered? Parkes receiver options| Graeme Carrad| | Page 16

  17. Priorities Parkes • Are there other options? • Is the high frequency multibeam the lower priority of the three considerations? • We are likely to investigate both, but if there was a preference for investigating wideband receiver or PAF which would it be? • We feel our wideband approach is less risky than the ‘all eggs in one basket’ consideration of the lower frequency receiver only. Compact Array • Future ATUC meeting - The case for going to 12.2 GHz on the ATCA. Parkes receiver options| Graeme Carrad| | Page 17

  18. Thank you • CSIRO Astronomy and Space Science Graeme CarradAssistant Director - Engineering t +61 2 9372 4305 e Graeme.Carrad@csiro.au w www.csiro.au/lorem • CSIRO Astronomy and Space Science CSIRO Astronomy and Space Science Mark BowenGroup Leader – Front End Technologies t +61 2 9372 4356 e Mark.Bowen@csiro.au w www.csiro.au/lorem

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