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Band 2 Workshop Introduction Band 2 Design Study Summary. E. Bryerton , M. Morgan, M. Pospieszalski , S. Srikanth , K. Saini , D. Vaselaar. Band 2 Workshop Schedule.
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Band 2 Workshop IntroductionBand 2 Design Study Summary E. Bryerton, M. Morgan, M. Pospieszalski, S. Srikanth, K. Saini, D. Vaselaar
Band 2 Workshop Schedule 09:00-09:30 Design Study Overview (Bryerton)09:30-09:50 GBT 4mm Receiver (Frayer)09:50-10:10 UAz 4mm Receiver - Part 1 Technical (Lauria)10:10-10:30 UAz 4mm Receiver - Part 2 Observations (Ziurys)10:30-10:45 Break [WebEx & audio inactive]10:45-11:10 Star Formation (Oberg)11:10-11:35 Deuterium-Bearing Molecules in Dense Cores (Schnee) 11:35-12:00 The Evolution of N2H+ and N2D+ in the Protostellar Phase (Tobin)12:00-12:30 NH2D and CH2D+ (Wootten)12:30-13:30 Lunch (supplied by workshop) [WebEx & audio inactive]13:30-14:00 Studies of Star Formation in the Nearby Universe (Mangum)14:00-14:20 Redshifted Molecular Gas (Frayer)14:20-14:45 Discussion of science drivers 14:45-15:15 Panel Discussion15:15-15:30 Break [WebEx & audio inactive]15:30- Workshop summary and adjourn Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 Frequency Range • Band 3 is 84-116 GHz • Current Band 2 Spec is 67-90 GHz Band 2 Workshop Charlottesville, VA 29-May-2013
Where Would Band 2 Go? Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 Workshop Goals • Focus on uniqueness of science case • Some technical overviews at beginning for context • Open discussion encouraged • Questions now: • How much overlap with band 3 is desirable? • Is extending band 3 below 84 GHz (to ???) an option? Only if performance in current band 3 range is unaffected? • Question to answer in ~2 years time • Is full installation of band 2 receivers on ALMA worth the approximate $12M price tag? Band 2 Workshop Charlottesville, VA 29-May-2013
ALMA Development Program • Funding lines in NA, EU, and EA • Two types: Design Studies & Development Projects • Development Projects • Funding ramps up to $13.6M per year total from all partners in 2015 • ~$5M per year from NA • Required ASAC approval and JAO coordination • $500K per year per partner in design studies (strictly regional) • One-year, <$200K • Current NA and EU band 2 efforts are design studies Band 2 Workshop Charlottesville, VA 29-May-2013
Current Development Projects • Band 5 Construction • European led effort for full installation of band 5 on all antennas • ESO spending ~$16M from 2013-2017 (all their project funding) • NA-NRAO supplying LO (~$3M) • Fiber Connection OSF-Santiago • 25x increase in data rate • ALMA Phasing Project (VLBI) • $0.52M from ALMA-NA, remaining funds from NSF MRI • Band 1 (EA) • Nov. 2012: ALMA Board approved development of prototype band 1 receiver Band 2 Workshop Charlottesville, VA 29-May-2013
NA FY14 ALMA Development Call for Proposals • Development Projects • $4.3M total available in FY14 and FY15 • $1.5M maximum award (over two-year period) • Design Studies • $1M available in FY14 • Will be another call for FY15 ($500K available) Band 2 Workshop Charlottesville, VA 29-May-2013
European Band 2 (+3) Design Study • 18-month study begun in June 2012 (STFC / IRAM / INAF) • Deliverables: Science case, study of key technologies to develop a band 2 or a band 2+3 cartridge design • Science Workshop held earlier this week Band 2 Workshop Charlottesville, VA 29-May-2013
NA Band 2 Design Study Overview • Joint NRAO-ARO Study • Oct. 2012 – Sep. 2013, $100K • Concentrate on demonstrating technology readiness of key components • Low-noise amplifiers • OMT • Optics • Downconverter • Science Motivation • Unexplored bandwidth, especially with interferometry • Deuterated species in cold cores • Galaxies at intermediate redshift • Complex organics Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 Gain/Noise Budget Table 2: Preliminary gain and noise budget for the ALMA band 2 receiver. • Current ALMA Band 2 Noise Specification: 30 K SSB over 80% of the RF band and 47 K SSB at any RF frequency in the band, where the RF band is defined as 67-90 GHz. • Given baseline optics design (warm refractive optics), this is extremely difficult and perhaps impossible (requires LNA with <15K noise temperature) • Slightly more realistic would be cold lens and a LNA with 20K noise temperature • Really need reflective optics, but may not fit (currently under study) Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 Turnstile-Junction OMT • X-band (8-12 GHz), Ku-band (11-18 GHz), and Q-band (35-52 GHz) versions already demonstrated • Band 2 version (currently in fabrication) will be ~32 grams (not including #0-80 screws) Band 2 Workshop Charlottesville, VA 29-May-2013
Band 1 OMT Measurements • Three Band 1 OMTs fabricated and measured Band 2 Workshop Charlottesville, VA 29-May-2013
Insertion Loss In Al, Au Band 1OMTs Gold Plating Nominal zincate Alkali copper : 25μ “ Pur-a-gold 125: 50μ “ S21 0.3 to 0.35 dB Theory 0.34 dB at 40 GHz for Au Predicted S21 of 0.12 dB at 15K Band 2 Workshop Charlottesville, VA 29-May-2013
Proposed Band 1 OMT and Amplifier Layout • Band 2 Cartridge layout will be similar Band 2 Workshop Charlottesville, VA 29-May-2013
Low Noise Amplifiers for Band 2 3-stage MMIC LNA (MMIC-A and MMIC-B two different designs) 6-stage hybrid LNA (WM###) Band 2 Workshop Charlottesville, VA 29-May-2013 16
Low Noise Amplifiers for Band 2 • Two 35nm MMIC designs have been tested, both 3-stage with ~30dB gain • 2 of 3 35nm wafer runs so far have given good cold results (4th run preliminary results encouraging) • Samples from APRA3 35nm wafer recently delivered, will be tested this summer • Broadband Cryo3 MIC LNA to be tested this summer • Current generation of 35nm MMIC design are 3-stage, 30 dB gain. Would really like 4-stage, 40 dB gain (eliminates need for 2nd cold LNA) Band 2 Workshop Charlottesville, VA 29-May-2013
Proposed Band 2 Block Diagram Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 Multi-Chip I/Q-Mixer LO=75 GHz • Commercial MMIC mixers • Machined RF quadrature hybrid and LO splitter • Tested with external Band 6 IF hybrid (coaxial, not shown) LO=80 GHz Band 2 Workshop Charlottesville, VA 29-May-2013
Band 2 MMIC I/Q-Mixer Chip Photo Simulated Performance (fixed IF) Band 2 Workshop Charlottesville, VA 29-May-2013
The National Radio Astronomy Observatory is a facility of the National Science Foundationoperated under cooperative agreement by Associated Universities, Inc. www.nrao.edu • science.nrao.edu Band 2 Workshop Charlottesville, VA 29-May-2013