Components, Receivers, and Instrumentation for Ground-Based
mm/submm Astronomy
B.Lazareff, G.Butin, M.Carter, J.Y.Chenu, A.L.Fontana, S.Mahieu, D.Maier, F.Mattiocco,
P.SerresK.Schuster, N.Krebs, T.Scherer, M.Schicke
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Outline
• Existing facilities• Drivers for development• Component technologies• Ultimate limits
• Device development at IRAM• SIS Mixers• Receiving systems• Instrumentation
• Future prospects
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Present and Future Facilities
• IRAM • ALMA
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Drivers for Receiver Development
• Sensitivity ! Ultimate limit: background limited• Receiver : electronics, optics• Atmosphere• Photon statisitics
• Frequency coverage• Tuning range. All atmospheric windows• Instantaneous. Goal: one atmospheric window, several 10's
of GHz!
• Speed (mapping)• But also:
• Stability: amplitude, phase• Linearity• Polarization purity• Reliability• Cost (hardware and manpower)
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Active Component Technologies
SIS
HEMT HEB
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Active Component Technologies
• HEMT• Direct amplification 115 GHz on telescopes; 200 GHz in the lab• Instantaneous b/w ~ 30%
• SIS• Heterodyne mixing 700GHz (Nb); >1THz (NbTiN)• Instantaeneous b/w 2 x 8 GHz
• HEB• Heterodyne mixing Several THz• Instantaeneous b/w ~ 4 GHz
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Active Component Technologies
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Pushing the Limits of Ground-Based Observing: 1.037 GHz !
Meledin et al 2004
CFA, Cambridge, MA
Moscow State University
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Quantum Limit for SIS mixers(after A.R.Kerr)
Receiver type SSB DSB
Calibration type SSB SSB DSB
Tsys kh / kh / kh 2/
Tmxr kh 2/ 0 0
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Fundamental Limits versusState-of-Art (ALMA specs, SSB)
Quantum
Atm (0.5mm PWV, 1.4 airmass)
ALMA SSB Spec
Practical limit
kh /1
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Devices : SIS Junction Devt & Fab
Area (m2)
Area Tol. (%)
Critical current density (kA/cm2)
Quality RSG[2mV]/RN
Process Yield (%)
1-4 10 6-15 15-30 >60
P2-I1-43.41-3
0
20
40
60
80
100
120
140
160
0 1 2 3 4 5 6
Voltage [mV]
Cu
rren
t [µ
A]
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Devices : SIS Junction Devt & Fab
• PdBI Band 1 (83-116 GHz)junction
• ALMA Band 7 (275-373 GHz)junction
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Devices : HEB Mixer Devt & Fab
Evolution of Tc with NbN film thickness
0
10000
20000,0
4 8 12 16 20
Temperature [K]
R [Ohm] 2.5 nm
3.3 nm
4.2 nm 5.8 nm
8.3 nm 12.5 nm
Optimisation systématique des films minces NbN
Mélangeur NbN : Courbe I/V et puissance IF
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Devices : MEMs : Tunable Capacitors
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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SIS Mixers
• DSB• SSB• 2SB (sideband separating)
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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DSB Mixers : Results
IRAM ALMA B7
Trec = 2 h/k
SRON ALMA B9
Trec = 3 h/k
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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SSB Mixers (PdBI) : Principle of Operation
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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SSB Mixers; Results for PdBI 200-260 GHz
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Sideband Separating (2SB) Mixersfor ALMA Band 7
Band 7 (IRAM)275 – 373 GHz
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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2SB SIS Mixer: Principle of Operation
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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ALMA Band 7 (IRAM) 2SB MixersResults
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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ALMA Band 7 (IRAM) 2SB MixersMore Results
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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ALMA Band 7 (IRAM) 2SB MixersMore Results
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Receiving Systems : PdBI
New generation receivers for PdBI. 4 frequency bands Dual-Pol 4GHz wide IF#1 unit currently undergoing system test
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Receiving Systems Atmospheric Phase Correction
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Receiving Systems : ALMA B7 Cartridge
• 275 – 373 GHz• Dual polarization• Dual sideband
USB+LSB• Four IF outputs
4 – 8 GHz• 147 K SSB
maximum• And many more
specs…
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Instrumentation : Antenna Range
• Herschel B1 horn verification
• 50 dB dynamic range @ 604 GHz
• ALMA B7 cartridge, optics verification
• >50dB dynamic range @ 300 GHz
arg Sbeam( )
20 log Sbeam 0.001( )( )
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Instrumentation : Vector Network Analyzer. 80 – 370
GHz
260 280 300 320 340 360
-60
-50
-40
-30
-20
-10
0
10
260 - 370 GHz MNVA multi holes coupler model and measurement
Leve
l [ d
B ]
Frequency [ GHz ]
Model losses (without conductivity losses) Model coupling Model isolation Measured coupling Measured isolation Measured losses
19-20 Sep 2005 Hunt for Molecules. Rx Devt for IRAM & ALMA Telescopes. B.Lazareff
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Where Do We Go from Here ? Areas for Future Work
• Array receivers for mapping speed• Push the IF b/w of SIS receivers to the limits:
f/f ~ 10% ?• Design integrated pixels• Push HEMT receivers to lower noise and higher
frequencies:• 30K over 85 – 115 GHz ?• ?? over 130 – 170 GHz ?
• Any really new detector around the corner ?• Keep our spectral bands pollution-free !