Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array Band 2 Workshop Introduction Band 2 Design Study Summary E. Bryerton, M. Morgan, M. Pospieszalski, S. Srikanth, K. Saini, D. Vaselaar
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Atacama Large Millimeter/submillimeter Array Karl G. Jansky Very Large Array Robert C. Byrd Green Bank Telescope Very Long Baseline Array Band 2 Workshop.
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Atacama Large Millimeter/submillimeter Array
Karl G. Jansky Very Large ArrayRobert C. Byrd Green Bank Telescope
Very Long Baseline Array
Band 2 Workshop IntroductionBand 2 Design Study Summary
E. Bryerton, M. Morgan, M. Pospieszalski, S. Srikanth, K. Saini, D. Vaselaar
ALMA
2
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
ALMA
Band 2 Frequency Range
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• Band 3 is 84-116 GHz• Current Band 2 Spec is 67-90 GHz
ALMA
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Where Would Band 2 Go?
Band 2 Workshop Charlottesville, VA 29-May-2013
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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?
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ALMA
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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
ALMA
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
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ALMA
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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)
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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
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NA Band 2 Design Study Overview• Joint NRAO-ARO Study• Oct. 2012 – Sep. 2013, $100K• Concentrate on demonstrating technology readiness of key
• 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
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Band 2 Gain/Noise Budget
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Component/Stage Gain (dB) Noise Temperature (K) TEQ (K) referenced to the input
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 version (currently in fabrication) will be ~32 grams (not including #0-80 screws)
ALMABand 1 OMT Measurements
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• Three Band 1 OMTs fabricated and measured
ALMAInsertion Loss In Al, Au Band 1OMTs
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Gold PlatingNominal zincateAlkali copper : 25μ “
Pur-a-gold 125: 50μ “
S21 0.3 to 0.35 dB
Theory 0.34 dB at 40 GHz for AuPredicted S21 of 0.12 dB at 15K
ALMAProposed Band 1 OMT and Amplifier Layout
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• Band 2 Cartridge layout will be similar
ALMA
60 65 70 75 80 85 90 95 1000
20
40
60
80
100
120
140
160
180
200MMIC-A1
MMIC-A2
MMIC-A3
MMIC-B1
WM022C
WM024C
WM025C
WM026C
WM027C
WM060C
Frequency (GHz)
No
ise
Tem
p [
K]
Low Noise Amplifiers for Band 2
16Band 2 Workshop Charlottesville, VA 29-May-2013
3-stage MMIC LNA (MMIC-A and MMIC-B two different designs)
6-stage hybrid LNA (WM###)
ALMA
Low Noise Amplifiers for Band 2
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• 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)
ALMA
Proposed Band 2 Block Diagram
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